The Head and Neck

Chapter 2

The Head and Neck

CONTENTS

2.1 Eagle Syndrome 36 2.2 Hyperostosis Frontalis Interna 37 2.3 Craniofacial Fibrous Dysplasia and Its Anomalies 38 2.4 Gardner Syndrome 41 2.5 Choanal Atresia 42 2.6 Congenital Cystic Lesions of the Head and Neck 43 2.7 External Auditory Canal Atresia 49 2.8 Congenital Anomalies of the Internal Ear (Congenital Hearing Loss) 50 2.9 Hearing Loss Syndromes 53 2.10 Petrous Bone Vascular Anomalies 56 2.11 Orbital Anomalies 59 2.12 Congenital Cholesteatoma 64

J. A. Al-Tubaikh, M. F. Reiser: Congenital Diseases and Syndromes – An Illustrated Radiological Guide DOI:DOI: 10.1007/978-3-642-00160-4_2, 10.1007/978-3-642-00160-4, © Springer-Verlag Berlin Heidelberg 2009 36 Chapter 2 The Head and Neck

2.1 Symptoms are believed to be caused by compres- Eagle Syndrome sion of the external carotid artery, internal jugular vein, or cranial nerves (9, 10, and 11) by the deviated, calcifi ed stylohyoid ligament, or by a fi brous tissue scar post tonsillectomy. Eagle syndrome (ES) is a disease characterized by cervicofacial pain caused by elongation of the styloid process, Signs on Radiographs which occurs due to extensive ossifi cation of the stylohyoid ligament (Fig. 2.1.1). ES is noted to occur in Lateral plain radiographs of the skull and neck show elongation some patients with a previous history of tonsillectomy. of the temporal styloid process until it reaches the hyoid bone The disease has an incidence of 4% in the general (classic sign) (Fig. 2.1.2). population, with a female predominance. The typical ES patient is female between 30 and 50 years of age with an elongated styloid process and cervicofacial pain. ES can be asymptomatic, while some patients present with cervicofacial pain in the distribution of the carotid artery, neuralgia of the pharynx, dysphagia, and alteration in taste. Other patients present with chronic headaches with pain in the ophthalmic and the occipi- tal regions when they turn their heads. This pain is cla- ssically seen due to bilateral internal carotid artery compression. The key diagnostic presentations of ES according to otolaryngologists include a patient with throat pain radiating to the ear post tonsillectomy and a patient with a throbbing pain through either the external or the internal carotid artery distribution.

Fig. 2.1.2. Lateral plain radiograph of the neck showing the elongated temporal styloid process with the calciﬁ ed stylohyoid ligament (black arrowheads) reaching up to the hyoid pone (white arrowhead)

For Further Reading

1. Gustavo M et al. Three-dimensional identifi cation of vascular compression in eagle's syndrome using computer tomography: Case report. J Oral Maxillofac Surg 2008;66:169–176 2. Beder E et al. Current diagnosis and transoral surgical treatment if eagle's syndrome. J Oral Maxillofac Surg 2005; Fig. 2.1.1. Illustration of a calcifi ed stylohyoid ligament with 63:1742–1745 elongation of the temporal styloid process. The calcifi ed ligament 3. Mendelson AH et al. Heterogeneity in the clinical presenta- presses over the vascular and neural contents of the carotid tion of eagle's syndrome. Otolarngol Head Neck Surg 2006; sheath 134:389–393 CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 37

2.2 Hyperostosis Frontalis Interna ) Axial bone-window CT of the skull shows bilateral CT of the skull shows Axial bone-window with giant cell arteritis. Mod Rheumatol 2008;18:181–183 with Rheumatol Mod arteritis. cell giant 1999;41:44–45 Neuroradiology MRI. interna: 1949;6(3):329–335 Am J Med interna. sis frontalis Signs on CT of the inner thickening symmetrical increased almost Bilateral, 2.2.2). (Fig. surface bone of the frontal arrowheads For Further Reading Further For 1. in a patient interna frontalis Hyperostosis H et al. Kocabas 2. frontalis hyperostosis exuberant Unusually G et al. Chaljub 3. with associated Endocrinopathies hyperosto- FE. Harding Fig. 2.2.2. 2.2.2. Fig. increase in the thickness of the inner surface of the frontal bone ( arrow- a syndrome characterized by a syndrome characterized by A lateral plain radiograph of the skull shows increased of the skull shows A lateral plain radiograph ) Patients with HFI may suffer from headache and suffer with HFI may Patients syndrome: Morgagni Signs on Plain Skull Radiographs Signs on Plain Skull 2.2.1). bone (Fig. of the inner frontal thickening is increased There Hyperostosis Frontalis Interna Frontalis Hyperostosis obesity, hirsutism (abnormally excessive hair growth), hair growth), excessive hirsutism (abnormally obesity, and HFI. neuropsychiatric diseases like epilepsy and dementia. neuropsychiatric diseases like endo- to various HFI has been linked Additionally, and goiter, crinopathies such as diabetes mellitus, toxic acromegaly. Hyperostosis frontalis interna (HFI) is a benign normal internaHyperostosis frontalis is a benign (HFI) increased characterized by cause of unknown variant of bone of the inner vault thickness of the trabecular frontal bone. HFI is a progres- the the skull affecting It has an incidence of and symmetrical process. sive women population. HFI affects 4–5% in the general to 40% of cases are seen in post- more than men (up menopausal women). 2.2 bone thickness in the inner surface of the frontal bone ( heads Fig. 2.2.1. 2.2.1. Fig. 38 Chapter 2 The Head and Neck

2.3 McCune-Albright syndrome: is a rare disease Craniofacial Fibrous Dysplasia affecting young female subjects characterized by poly- and Its Anomalies ostotic fi brous dysplasia, precocious puberty, and skin hyperpigmentation. Cherubism: is a term used to describe symmetrical involvement of the maxilla and mandible producing Craniofacial fi brous dysplasia (CFD) is a disease of bilateral, progressive swelling of the cheeks (Fig. 2.3.2). unknown origin characterized by replacement of the It can be caused by CFD and giant cell lesions (Fig. 2.3.3). normal bone and bone marrow by fi brous tissues; it Cherubism is a benign condition with an autosomal affects any bone in the body. dominant mode of inheritance. Typically, it presents The disease may affect a single bone (called mono- around the age of 7 years and tends to regress after stotic fi brous dysplasia) or multiple bones (called poly- adolescence. ostotic fi brous dysplasia). CFD occurs in 20% of the Mazabraud syndrome: is a rare disease character- general population and is commonly associated with ized by the association of polyostotic fi brous dysplasia the polyostotic form of the disease. The peak incidence with intramuscular myxoma. is in children and teenagers (before 30 years of age). The common presentation is a young child brought in by the parents due to facial swelling and asymmetry. Signs on Plain Radiographs Other clinical presentations involve unilateral proptosis due to orbital bone involvement. Visual disturbance may Diff use thickening and sclerosis of the aff ected facial bones with occur as a result of optic nerve compression secondary to classic “ground glass” appearance due to the fi brous matrix optic foramen stenosis by the expanded, sclerotic bones. nature of the disease. Leontiasis ossea: is a rare form of CFD with extensive maxillary involvement leading to maxillary encroach- ment on the orbital cavities, mouth, and paranasal sinuses, which produces a wide facial appearance likened to a lion's face (Fig. 2.3.1, 2.3.4, and 2.3.5).

Fig. 2.3.1. Illustration of a patient with bilateral leontiasis ossea. Note the wide face that looks like the characteristic face of a Fig. 2.3.2. Illustration of a young girl with bilateral full cheeks lion. Also, note the hypertelorism resulting from distension of (cherubism). Cherubism is a term used to describe bible drawings the facial bones of children with full cheeks CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 39

brous content brous brous dysplasia involving the left clavarium and the left clavarium brous dysplasia involving 2.3 Craniofacial Fibrous Dysplasia and Its Anomalies open brous ). Note Note the a arrows Extensive Extensive b ) caused by the ) caused by Axial and coronal Axial and coronal Sagittal, coronal, and axial T1-weighted MR images show extensive fi extensive MR images show T1-weighted Sagittal, coronal, and axial Axial bone- window window Axial bone- brous dysplasia brous ). Bilateral involve- ). The lesion has a ). arrows brous dysplasia is termed arrows ment of the mandible by by mandible ment of the fi cherubism bone-window CT scan of a CT bone-window unilateral fi patient with the mandible dysplasia of ( Fig. 2.3.3. 2.3.3. Fig. the left facial distension ( arrowheads lesion compared with the normal right side Fig. 2.3.5. 2.3.5. Fig. involvement of the left involvement maxillary sinus, zygomatic bone, and the petrygoid plates seen ( is clearly signal of the lesion due to its fi Note the hypointense the left paranasal sinuses in another patient with CFD. classic “ground glass” appearance. CT images of a patient with leontiasis ossea. ( Fig. 2.3.4. 2.3.4. Fig. of the involvement extensive left foramen rotundum, greater wings of the sphenoid, petrygopalatine and its fossa canal, basisphenoid bone, posterior ethmoid air cells, and fi by clivus 40 Chapter 2 The Head and Neck

Paget disease of the skull (found in older age-group Signs on CT and affects both the facial bones and the clavarium extensively, in contrast to fi brous dysplasia which The involved bones appear expanded with intact inner and can extensively affect the facial bones without affect- outer surfaces (Fig. 2.3.4). ing the clavarium). The bone may show osteolytic features or sclerotic features depending on the matrix calcifi cation rate. Small orbit sign: a decrease in the size of the orbit due For Further Reading to bony orbit expansion. 1. Jain V et al. Radiographic, CT and MRI features of cherubism. Pediatr Radiol 2006;36:1099–1104 Signs on MRI 2. Carbral CEL et al. Polyostotic fi brous dysplasia associated with intramuscular myxoma: Mazabraud's syndrome. Skeletal Radiol 1998;27:278–282 The bones show expansion with low signal intensity in 3. Yüceer N et al. Polyostotic fi brous dysplasia with craniofacial T1-weighted sequence with inhomogeneous gadolinium localization presenting with frontal lobe compression in a enhancement due to the fi brous nature of the lesion (Fig. 2.3.5). 14-year-old Girl. Acta Neurochir (Wien) 1999;141:203–207 4. Mendonca JJ et al. Fibrous dysplasia of the mandible: Surgical treatment with platelet-rich plasma and a cortico- cancellous iliac crest graft-report of a case. Oral Surg Oral Differential diagnosis: Med Oral Pathol Oral Radiol Endod 2008;105: e12–e18 Ossifying fi broma of the head and neck (localized 5. Sherman NH et al. Fibrous dysplasia of the facial bones and to one bone and rarely crosses to another bone. It mandible. Skeletal Radiol 1982;8:141–143 6. Maramatton BV. Leontiasis ossea and post traumatic cervi- also has a female predominance, with age of presen- cal cord contusion in polyostotic fi brous dysplasia. Head tation in the third to fourth decade). Face Med 2006;2:24. doi 10.1186/1746–160x-2–24 CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 41

2.4 Gardner Syndrome 2.4 Gardner prolif- brous soft-tissue ) gurement related with Gardner's syndrome: with syndrome: Gardner's related gurement arrowhead Plain radiograph of the skull shows ivory osteoma of ivory of the skull shows Plain radiograph reoc- of the adjacent tissues and tends to ltration steomas of the skull, angle of the mandible, or its inferior or its inferior of the mandible, angle of the skull, steomas O surface (Fig. 2.4.2). surface (Fig. teeth. and unruptured hypoplasia, Dental anomalies, in the long bones. (hyperostosis) Cortical thickening

causing disfi causing Larynx Nauses 2003;30:447–445 Auris Case report. 89–92 Oral Oncology 2005;41: EXTRA case. 2001;45:940–942 Congenital hypertrophy of the retinal pigment epi- of Congenital hypertrophy Desmoid tumor is a benign fi Desmoid tumor Signs on Plain Radiographs Fig. 2.4.2. 2.4.2. Fig. ( the clavarium Reading Further For 1. of osteomas the mandible huge Multiple T et al. Baykul 2. syndrome-review of and report Gardner a J et al. Butler 3. Dermatol Acad Am J syndrome. Gardner ET et al. Parks cur after surgical excision. It is seen in 8.9% of cases. It is seen in excision. cur after surgical be seen in up to 85% of cases. thelium (CHRPE) can eration that occurs in the skin or inside the abdomen. It or inside the abdomen. occurs in the skin eration that it has an aggres- however, tendency; has no malignant infi sive Illustration of the classic locations of Gardner syndrome Illustration of the classic locations of Gardner The intestinal polyposis is hereditary with a 100% The intestinal polyposis island that can be made up bony Osteoma is a benign abnor- presents with dental The disease commonly Epidermoid in the face, present scalp, and cysts Gardner Syndrome Gardner osteomas, at the angle of the mandible and its inferior surface osteomas, at the angle of the mandible Fig. 2.4.1. 2.4.1. Fig. Gardner syndrome is a rare, hereditaryGardner syndrome is disease charac- (made of adenomas), polyposis intestinal terized by and multiple in the jaw), (mainly multiple osteomas lesions (epidermoidcutaneous and subcutaneous cysts and desmoid tumor). transformationchance of malignant if not treated. trabecular bone. In Gardner syn- or of compact (ivory) and in the jaw found drome, osteomas are commonly the most characteristic and diag- the skull. In the jaw, are thenostic locations for Gardner syndrome osteomas 2.4.1). mandibular angle or its inferior surface (Fig. sign and symp- Mandibular osteomas can be the initial tom of Gardner syndrome. supernumer- malities (30%) such as dental hypoplasia, ary teeth, and compound odontomas. in around 50% of cases. extremities 2.4 42 Chapter 2 The Head and Neck

2.5 Choanal Atresia Signs on Paranasal Sinus CT

Axial CT images demonstrate thickening and medial bowing of the lateral wall of the nasal cavity with atresia of the posterior Choanal atresia is an uncommon sinusoidal malforma- choana. Fusion between the vomer and the palatine bones tion characterized by unilateral or bilateral closure of obstructing the opening to the nasopharynx is usually seen. the communication between the posterior nasal choana Membranous atresia is seen as an isodense soft-tissue mass and the nasopharynx. The closing ridge is bony in 90% closing the passage between the posterior choana and the of cases and membranous in 10% of cases. nasopharynx (Fig. 2.5.2). Up to 50% of neonates with choanal atresia have craniofacial, cardiovascular, or visceral congenital malformations (e.g., CHARGE association). CHARGE association is a congenital syndrome characterized by coloboma, heart disease, atresia of the choanae, retarded mental development, genital hypoplasia, and ear anomalies and deafness. Neonates with bilateral choanal atresia present with respiratory distress in the immediate newborn period. In contrast, unilateral choanal atresia may be diagnosed later in life.

Signs on Plain Radiographs

Lateral radiographs demonstrate a discrete separation between the air in the nasopharynx and the air in the posterior nasal cavity. Contrast material instilled into the nasal cavity in supine position will collect against the obstruction (Fig. 2.5.1). Fig. 2.5.2. Axial bone-window CT of the paranasal sinuses shows bilateral soft-tissue density masses blocking the passage of the posterior choana in a patient with soft-tissue choanal atresia (arrowheads)

For Further Reading

1. El-Sawy H et al. Bilateral choanal atresia and paranasal sinus hypoplasia in an adult patient with hypogammaglobulinae- mia. Eur Arch Otorhinolaryngol 2006;263:1136–1138 2. Koletzko B and Majewski F. Congenital anomalies in patients with choanal atresia: CHARGE-association. Eur J Pediatr 1984;142:271–275

Fig. 2.5.1. Plain radiograph of the skull base shows contrast material instilled into the nose with collection of the contrast material against an obstructed posterior choana in a patient with bony choanal atresia CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 43

) arrowhead ammation or trauma. The cyst The cyst ammation or trauma. 2.6 Congenital Lesions Cystic of the Head and Neck Axial noncontrast-enhanced head CT illustration shows shows Axial noncontrast-enhanced head CT illustration erential Diagnosis erential Mucosal cyst (exhibits low T1 signal intensity on MR images T1 signal intensity cyst low Mucosal (exhibits recess). in the lateral and is usually located cleft cystsBranchial their location). (by The cyst is located in the mid-posterior wall of the nasopharynx of the wall cyst in the mid-posterior The is located T1 (the high signal in T2 signal intensities T1 and high with high of the cyst). content depends on the protein material. injection after cyst enhance of contrast may The wall A hyperdense cyst located at the midline between the longus the midline between cyst at located A hyperdense The of the nasopharynx. wall capitis muscles and the posterior administration material cyst contrast after does not enhance 2.6.2). (Fig. occur. may cations Occasional calciﬁ

Signs on MRI Diff Signs on CT Thornwaldt Cyst (Pharyngeal Bursitis) Cyst Thornwaldt results from obstruction cyst pha- of the Thornwaldt ryngeal due to infl bursa midline in the posterosuperior wall located is typically of the nasopharynx. Fig. 2.6.2. 2.6.2. Fig. the longus capitis located between mass hyperdense a round, ( cyst Thornwaldt muscles representing a ) arrowhead ammatory conditions or, rarely, neoplastic rarely, ammatory or, conditions Axial head CT illustration shows a median recess Axial head CT illustration shows The scan shows a median recess that contains air between the air between contains that a median recess scan shows The 2.6.1). longus capitis muscles (Fig. Signs on CT and MRI nding. When the bursa becomes infected, it is called it is called infected, When the bursa becomes nding. Congenital Cystic Lesions Lesions Cystic Congenital and Neck of the Head “Thornwaldt cyst.” “Thornwaldt of the population as an incidental, asymptomatic asymptomatic incidental, an as the longus capitis muscles. It is seen in 7% between population the of fi The pharyngeal of Luschka is a median forma- bursa nasopharynxtion that projects in the midline of the The PharyngealThe Bursa of Luschka (e.g., Warthin tumor). Most of the cystic lesions are of the cystic tumor). Most Warthin (e.g., are diagnosed according to their seen in children, and location. Cystic lesions of the head and neck are usually either head and neck are usually Cystic lesions of the lesions are a Acquired in origin. congenital or acquired result of infl 2.6 Fig. 2.6.1. 2.6.1. Fig. the longus capitis muscles representing the pha- located between ryngeal ( bursa of Luschka 44 Chapter 2 The Head and Neck

Thyroglossal Duct Cyst lymphatic drainage. It involves lymphatic proliferation in the bones and viscera. The disease affects children The thyroid gland develops medially at the base of the and young adults. tongue and then descends anterior to the hyoid bone There are three forms of lymphangiomatosis: along the thyroglossal duct to its normal position. When Cystic form: this form is known as “cystic hygroma,” the thyroglossal duct fails to obliterate, it results in the and most commonly occurs in the neck or the axilla formation of a median or paramedian cyst. The normal in children. thyroglossal duct extends from the foramen cecum at Capillary form: this form affects the skin. the base of the tongue to the lower neck region where Cavernous form: this form affects the bone, soft the thyroid bed is. It is obliterated between the ﬁ fth and tissues, and the viscera. sixth weeks of gestation. Cystic hygroma is usually diagnosed before 2 years Thyroglossal duct cysts account for up to 70% of all of life. Typically, the cyst grows in size as the child cystic malformations in the neck. Up to 50% are grows. located at the hyoid bone, 25% below the hyoid and Cystic hygroma can be associated with genetic 25% above it. syndromes such as Turner syndrome, trisomy 21, 13, and 18. Signs on CT

Typically, the scan shows a median–paramedian cyst located at the level of the hyoid bone with no contrast enhancement Signs on CT and MRI (Fig. 2.6.3). The cyst typically splits the two anterior bellies of the Cystic hygroma appears as a cyst with a thin wall, and a diagastric muscles. water-dense mass with multiple lobules that do not enhance Ring contrast enhancement may be seen in cases of infected after injection of contrast material. The mass may show cyst. ﬂ uid–ﬂ uid levels due to intracystic hemorrhage (Fig. 2.6.4). The cyst shows ring contrast enhancement if superimposed by infection. Hypertrophy of the adjacent bony structures (e.g., mandible) may occur occasionally.

Fig. 2.6.3. Axial postcontrast neck CT shows a right paramedian hypodense cystic lesion at the level of the larynx representing a thyroglossal duct cyst (arrowhead)

Cystic Hygroma (Lymphangiomatosis)

Lymphangiomatosis is a rare disorder of unknown Fig. 2.6.4. Axial T1-weighted MR illustration shows cystic hygroma on the right side with typical ﬂ uid–ﬂ uid appearance origin characterized by diffuse proliferation of the within the cyst, and different intensities due to the cyst content lymphatic channels in the body with obstruction of (arrowhead) CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 45

without recur- This cyst occurs ante- This cyst This cyst occurs near the This cyst ear with or branchial cleft cyst rst 2.6 Congenital Lesions Cystic of the Head and Neck ) Axial T1-weighted MR illustration shows a medial MR illustration shows T1-weighted Axial Axial postcontrast head CT illustration shows a cyst a cyst Axial postcontrast head CT illustration shows external auditory canal or the parotid gland (Fig. 2.6.7). external auditory (Fig. canal or the parotid gland Patients It accounts for 8% of all branchial cleft cysts. present with a mass near the rior to the sternocleidomastoid muscle, lateral to the carotid sheath, and posterior to the submandibular - 2.6.8). It ac gland and the mandibular edge (Fig. Patients counts for 95% of all branchial cleft cysts. neck mass. present with a nontender lateral typically First Branchial Cleft Cyst: Branchial First rent infections. Cleft Cyst: Second Branchial

arrowheads Fig. 2.6.6. 2.6.6. Fig. hyperintense containing multiple mildly mass isointense cystic seen in dermoid and This appearance is typically small masses. appearance epidermoid resulting in a “sack of marbles” cysts ( Fig. 2.6.7. 2.6.7. Fig. located near the right external auditory canal and the parotid a typical site for fi gland, arrow- oor of fth weeks of fth weeks fattyuid but not rst four branchial apparatuses. Axial postcontrast neck CT shows large paramedian large Axial postcontrast neck CT shows ve pairs of ectodermal branchial clefts externally. pairs of ectodermalve clefts externally. branchial a characteristic “sack of marbles” appearance or fat–fl uid or fat–fl appearance of marbles” a characteristic “sack 2.6.6). (Fig. levels cyst. for thyroglossal can be mistaken They These lesions are commonly located medially within the neck, located commonly lesions are These 2.6.5). (Fig. thick walls and have can produce within the lesion fat oating On MRI, globules of fl )

Signs on CT and MRI pairs of endodermalve pharyngeal pouches internally gestation. Branchial cysts are malformationsgestation. Branchial cysts that usu- arise from the fi ally and fi the fourth and fi between develop They The branchial apparatus comprises structures com- posed of six pairs of mesodermal arches separated by fi Branchial CleftBranchial Cysts Fig. 2.6.5. 2.6.5. Fig. The mass center and very thick walls. mass with hypodense to be a malignant epidermoid biopsy ( after cyst proved head These lesions are commonly located medially within within located medially are commonly These lesions They thick walls. have and characteristically the neck, arising from the fl midline lesions are typically Dermoid and Epidermoid Cysts and Epidermoid Dermoid muscle. Dermoid the myelohyoid the mouth deep to glands, and hair follicles. contain skin, sebaceous cysts In contrast, epidermoid contain fl cysts material. 46 Chapter 2 The Head and Neck

Patients present before 20 years of age complaining of hoarseness, dysphagia, and respiratory distress.

Signs on CT

The scan shows a hypodense, cystic mass in the upper mediastinum or the lower neck causing tracheal deviation, or exerting mass eﬀ ect over the adjacent structures. The cyst is closely related to the carotid sheath.

Dentigerous (Follicular) Cysts

A dentigerous cyst is one that arises from a tooth after calciﬁ cation of its crown, and is usually located at the mandibular or the maxillary third molar tooth. The cyst can be large enough to occupy half of the mandible. The peak incidence is between 40 and 60 years of age. Dentigerous cysts can be associated with mucopoly- saccharidosis.

Signs on Radiograph or CT Fig. 2.6.8. Axial postcontrast head CT image shows typical location of the second branchial cleft cyst (arrowhead) A cystic lesion of the mandible with an eccentrically placed tooth crown (Fig. 2.6.9). Third Branchial Cleft Cyst: This cyst occurs posterior to the internal carotid artery in the upper neck; in the lower neck it can be found in the anterior triangle.

Signs on CT

The cysts appear as hypodense lesions that do not enhance after contrast medium administration. The origin of the cyst is determined according to its location.

Thymic Cysts

Normally, the thymus originates from the third branchial pouch during the ﬁ fth week of gestation. It detaches from the pharynx and migrates caudally and medially via the thymopharyngeal duct to reach its normal position in the upper mediastinum. The track of the thymopharyngeal duct extends from the angle of the man- Fig. 2.6.9. Coronal CT of the paranasal sinuses shows a large dible to the upper mediastinum. Thymic cysts occur due cyst that arises from the third maxillary molar tooth (dentigerous to persistence of remnants of the thymopharyngeal duct cyst). The cyst is expanding into more than half the space of the (like the thyroglossal duct cyst). right maxillary sinus (arrowhead) CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 47

) oor of the mouth arrowheads 2.6 Congenital Lesions Cystic of the Head and Neck Axial postcontrast CT of the ﬂ The cyst has low T1/high T2 signal intensities with a intensities T2 signal T1/high cystThe has low An inhomogeneous architecture. homogeneous internal the diagnosis of ranula. excludes architecture internal T2-weighted on uid signal sign is seen as a high ﬂ comet-tail The 2.6.12 and 2.6.13). (Figs. images within the sublingual space the submandibular space, reach Extension may the ranula of free This the parapharyngeal into or further space. upward no fascial boundaries are because there occurs extension and parapharyngeal submandibular, the sublingual, between spaces. Simple ranula: the scan shows a hypodense mass located in mass located a hypodense scan shows the Simple ranula: contrast after a ring enhancement with space the sublingual injection. material mass.” “comet-tail-shaped appears as a ranula Complicated is in and the head in the sublingual space tail is located The 2.6.11). (Fig. the submandibular space

Signs on MRI Signs on CT Fig. 2.6.11. 2.6.11. Fig. ranula ( complicated (diving) shows ammation nding in a patient results from rupture occurs due to obstruction of the sali- Illustration showing the clinical ﬁ Illustration showing Typically, the patient is between 25 and 30 years of of 25 and 30 years the patient is between Typically, vary gland duct without rupturing.vary It does not cross submandibular space. the boundaries of the ranula: Complicated (diving) space with forma- of the gland within the sublingual into the subman- that can extend tion of a pseudocyst dibular space. Simple ranula:

Patients often present with painless swelling of the sub- often present with painless swelling Patients 2.6.10). discoloration (Fig. lingual glands with bluish with ranula. Typically, there is a bluish mass found below the mass found below there is a bluish Typically, with ranula. ducts open the sublingual tongue, where Fig. 2.6.10. 2.6.10. Fig. The sublingual glands have 8–20 excretory 8–20 ducts that glands have The sublingual opening of the posterior to the the tongue open below is a retention Ranula Warton). duct (of subamndibular glands gland or the sublingual of the minor salivary cyst occurring after trauma or inﬂ most commonly Ranula ranulas are rare. of the mouth; congenital trauma to a history of previous age with 50% having the mandible. types: into two Ranulas are divided 48 Chapter 2 The Head and Neck

Fig. 2.6.12. Axial T2-weighted MR illustration of the fl oor of Fig. 2.6.13. Axial T2-weighted MR illustration of the fl oor of the mouth shows simple ranula seen as a homogeneous mass the mouth shows complicated ranula with its “comet tail sign” with defi ned boundaries 2. Koch BL. Cystic malformations of the neck in children. For Further Reading Pediatr Radiol 2005;35:463–477 3. Kurabayashi T et al. MRI of ranulas. Neuroradiology 2000; 42:917–922 1. Wong KT et al. Imaging of cystic or cyst-like neck masses. 4. Chong VFH et al. Radiology of the nasopharynx: Pictorial Clin Radiol 2008;63:613–622 essay. Australas Radiol 2000;44: 5–13 CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 49

rst branchial cleft branchial rst 2.7 2.7 External Auditory Canal Atresia ) Coronal bone-window CT images show absence of CT images show Coronal bone-window anomaly. Eur Arch OtorhinolaryngolArch 2006;263:263–266 Eur anomaly. of with atresia in patient congenital potentials myogenic Otorhinolaryngol J Pediatr Int canal. the external auditory 2001;57:25–29 Signs on Petrous Bone CT Signs on Petrous auditory ear of the external or blockage is absence canal, There 2.7.2 and 2.7.3). (Figs. a bone or soft tissue of the canal by arrowheads Fig. 2.7.3. 2.7.3. Fig. middle The the external auditory canal passage on the left ear. formation bone with no sign of EAC by is blocked ear cavity ( For Further Reading Further For 1. of the fi extension Unusual M et al. Ada 2. 2. evoked vestibular Bone-conducted Sheykholeslami K et al. rst branchial ). Note the normal Coronal Illustration rst branchial arches, and the fi rst branchial arches, ) EAC atresia is often associated with small, deformed atresia is often associated EAC or bone CT is performed to assess bony Petrous arrow arrowhead External Atresia Auditory Canal EAC passage on the right ear EAC ( Fig. 2.7.2. 2.7.2. Fig. CT images bone-window soft-tissue blockage show on the left ear of the EAC ( cleft in the embryo. External cleft in the embryo. auditory canal (EAC) of the underdevelopment by atresia is characterized external auditory canal. deformities or pinna (microtia), and in the mandible atresia 2.7.1). EAC joint (Fig. the temporomandibular malformation bilateral, but unilateral may is usually be associated with middle ear atresia can EAC occur. or facial anomalies (e.g., contracted middle ear cavity) anomalies (e.g., Goldenhar syndrome). associated middle ear abnor- and soft-tissue blockage A contracted middle ear malities (e.g., fused ossicles). with reconstructionmm is incompatible 3 below cavity surgery. The external the second and the middle ear arise from and the fi 2.7 Fig. 2.7.1. 2.7.1. Fig. absence of the shows entrance of the external auditory canal in a patient atresia with EAC 50 Chapter 2 The Head and Neck

2.8 Congenital Anomalies of the Internal Ear (Congenital Hearing Loss)

In normal embryological development of the ear, the bony labyrinth evolves between the 4th and 8th week of gestation, grows between from the 8th to the 16th week, and ossifi es from the 16th to 24th week. Development of the sensory epithelium occurs after the 25th week. Congenital malformation arises when an insult (e.g., intrauterine infection) occurs between the fourth and eighth weeks of gestation. Fig. 2.8.1. Axial petrous bone CT illustration shows complete absence of the cochlea, vestibule, and semicircular canals Up to 50% of cases of congenital anomalies of the (Michel anomaly) inner ear are due to genetic defects, and the remainder of cases are attributed to intrauterine infections (TORCH), Mondini Anomaly fetal drug ototoxicity, and trauma. Cytomegalovirus is a common infection that causes inner ear anomalies Mondini anomaly is a term used to describe fusion of and congenial deafness. Ingestion of ototoxic drugs by the apical and the middle cochlear turns making up one pregnant women can lead to congenital hearing loss; cavity, while the basal turn is present. examples are alcohol (fetal alcohol syndrome), amino- Up to 20% of patients with Mondini anomaly have glycosides, aspirin, erythromycin, and furosamide. other malformations of the vestibule, endolymphatic Up to 70% of genetic congenital hearing losses duct, or semicircular canals. occur as isolated cases, the rest of the genetic cases Patients with Mondini anomaly present with low- occur as parts of syndromes. frequency hearing defi cit, due to fusion of the apical and Presbycusis: is bilateral sensorineural hearing loss the middle cochlear turns. In contrast, high-frequency due to age. The CT scan shows a normal temporal struc- hearing persists due to presence of the basal turn. ture. Malformations that only involve the membranous labyrinth are classifi ed as Alexander and Scheibe defor- Signs on Petrous Bone CT mities. The CT examination of these deformities is normal. The scan shows fused apical and middle cochlear turns with loss of the cochlear modiolus (Fig. 2.8.2).

Michel Dysplasia

Michel dysplasia is a term used to describe complete absence of the entire middle ear, including the cochlea, vestibule, and all semicircular canals. The medial wall of the inner ear and the promontory are ﬂ at due to inner ear aplasia. It is a very rare anomaly, and its main differential diagnosis is postmeningitic labyrinthine ossiﬁ cation.

Signs on Petrous Bone CT

The scan shows complete absence of the inner ear (Fig. 2.8.1).

Fig. 2.8.2. Axial petrous bone CT illustration shows Mondini anomaly. Note the fusion between the apical and the middle cochlear turns with absence of the cochlear modiolus (arrowhead) CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 51

uid in the cranial ) arrowhead Axial petrous bone CT illustration shows loss of the Axial petrous bone CT illustration shows Signs on Petrous Bone CT Signs on Petrous the superior or the posterior defect a bony over scan shows The 2.8.4). canal (Fig. semicircular Signs on Petrous Bone CT Signs on Petrous of of one or more or underdevelopment agenesis shows scan The canals. the semicircular tibule to the posterior surface of the petrous temporal The normal aqueduct diameter measures vestibular bone. Large Vestibular Aqueduct Syndrome Vestibular Large aqueduct is a J-shaped (endolymphatic) The vestibular ves- of the from the medial wall canal that extends bony Semicircular Canal Dehiscence Canal Semicircular dehiscence is a condition charac- Semicircular canal posterior or of the overlay bony loss of the terized by The area of the bony canals. superior semicircular dura separating the semicir- by only defect is covered cerebrospinal ﬂ cular canal from the pressure within the intracranial fossa. Changes in the defect into the space can be transmitted through this resulting in vertigo. labyrinth Fig. 2.8.4. 2.8.4. Fig. semicircular canal, representing the superior over covering bony semicircular canal dehiscence ( 2.8 Congenital Anomaliesof the Internal Ear (Congenital Hearing Loss) Axial petrous bone CT illustration shows the common Axial petrous bone CT illustration shows fth week of gestation. of fth week Semicircular aplasia can be associated with syn- Signs on Petrous Bone CT Signs on Petrous of the vestibule the area occupying one cavity scan shows The 2.8.3). (Fig. and the cochlea association. lar canal is the most commonly affected. lar canal is the most commonly dromes such as Goldenhar syndrome and CHARGE ween the sixth and eighth week of gestation. There will of gestation. the sixth and eighth week ween one or or complete abscence of be underdevelopment more of the semicircular canals; the lateral semicircu- Aplasia or hypoplasia of the semicircular canal is an of the semicircular canal is an Aplasia or hypoplasia interruption that arises due to developmental anomaly bet- of the semicircular canals during embryogenesis Semicircular Canal Aplasia/Hypoplasia Canal Semicircular low cavity without internal due architecture. It occurs cavity low the fourth arrest between to inner ear developmental and ﬁ Common cavity deformity is characterized by replace- deformity by is characterized cavity Common a single hol- by cochlea and the vestibule ment of the Common Cavity Deformity Cavity Common cavity anomaly. Note the complete fusion between the vestibule the vestibule Note the complete fusion between anomaly. cavity cavity and the cochlea to form a single hollow Fig. 2.8.3. 2.8.3. Fig. 52 Chapter 2 The Head and Neck

up to 1.5 mm. Congenital enlargement of the vestibular aqueduct beyond this diameter results in progressive, Signs on MRI bilateral, sensorineural hearing loss and vertigo, com- The scan shows enlargement of the vestibular aqueduct on monly in the younger population. T2-weighted images with fl uid signal intensity (Fig. 2.8.6). The vertigo and the sensorineural hearing loss are attributed to damage of the hair cells within the labyrinth due to cerebrospinal fl uid pressure fl uctuation, which is delivered by the enlarged vestibular aqueduct.

Signs on Petrous Bone CT

The scan shows enlargement of the vestibular aqueduct beyond 1.5 mm in diameter (Fig. 2.8.5).

Fig. 2.8.6. Axial T2-weighted MR image in another patient shows markedly enlarged vestibular aqueduct (arrowhead)

For Further Reading

1. Kavanagh KT and Magill HL. Michel dysplasia, Common cavity inner ear deformity. Pediatr Radiol 1989;19:343–345 2. Davidson HC. Imaging of the temporal bone. Neuroimag Clin N Am 2004;14:721–760 3. Naganawa S et al. Serial MR imaging studies in enlarged endolymphatic duct and sac syndrome. Eur Radiol 2002; Fig. 2.8.5. Axial petrous bone CT image shows an enlarged ves- 112:S114–S117 tibular aqueduct (arrowhead) 4. Krombach GA. Imaging of congenital anomalies and acquired lesions of the inner ear. Eur Radiol 2008;18(2): 319–330 CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 53

lbi- a this disease has it is the classic form, 2.9 2.9 Hearing Loss Syndromes cation defect that causes (two eyes with different colors, with different eyes (two is a rare variant expression of expression is a rare variant it is a combination of type 1 with it is a combination of type 2 with ell migration disorder of the gut c eafness. The disease has an auto- eafness. (whitish or grayish hair in the front hair or grayish (whitish d lack lock, b ABCD syndrome: syndrome, up to 80% of the thyroid- In Pendred The sensorineural hearing loss is often caused by Signs on Petrous Bone CT Signs on Petrous in 17% of cases, present bone are Abnormalities of the petrous canals and the vestibule. and include aplasia of the semicircular Shah syndrome): Hirschprung disease. White forelock of the head). irides Heterochromia type 1: syndrome Waardenburg mentioned with the above- and the patient presents features. type 2: syndrome Waardenburg type 1 but lacks the dystopia the same features as canthorum. type 3 (Waardenburg- syndrome Waardenburg Klein syndrome): upper limb anomalies (e.g., syndactyly). type 4 (Waardenburg- syndrome Waardenburg or one eye with two different colors in the iris). different two with or one eye sensorineural hearing loss. Congenital bilateral

syndrome characterized by Waardenburg-Shah nism, and neurocytes, mode of inheritance. somal recessive Syndrome Pendred disease syndrome is an autosomal recessive Pendred hear- congenital sensorineural severe characterized by ing loss with iodine organiﬁ The disease goiter in infants. thyroid developmental accounts for almost 10% of all cases of congenital hearing loss syndromes. on administration of accumulated iodide is discharged The perchlorate test a substance called “perchlorate”. is the gold standard test for diagnosing this disease. aque- vestibular or bilateral enlarged Mondini anomaly duct syndrome. subtypes The disease has four (lateral displacement of the (the eyebrows grow together). grow (the eyebrows dystopia ), the ), the ) The disease has an autosomal dominant mode of The disease has an autosomal dominant inner canthi, or inner angles of the eyes, plus lateral inner canthi, or inner angles of the eyes, displacement of the lacrimal puncta). Prominent broad nasal root. Synophrys Dystopia canthorum

heterochromia heterochromia synophrys Hearing Loss Syndromes Loss Hearing white forelock, and white different the two colors of the iris ( irides prominent broad nasal root, the adjacent eyebrows ( Fig. 2.9.1. 2.9.1. Fig. the Illustration shows typical facial features of Waardenburg syndrome. Note the lateral displacement of the medial angles ( of the eye canthorum Waardenburg Syndrome Waardenburg syndrome is a rare congenital disorder Waardenburg characteristic facial features, pig- distinguished by congenital, sen- mented abnormalities, and profound, sorineural hearing loss (up to 75% of cases). births. It live inheritance, with an incidence of 1:40,000 loss cases. accounts for 2% of all congenital hearing 2.9.1): (Fig. syndrome is characterized by Waardenburg Hearing loss can occur due to aging, trauma, as well as due to aging, trauma, as well Hearing loss can occur drug-relatedCongenital hearing and congenital causes. “syndromic” and “nonsyndromic” into loss is divided type, hearing loss occurs as parttypes. In the syndromic other manifestations within theof a syndrome with loss syndromes that cause hearing are many There body. four of the most Only as one of their manifestations. syndromes are discussed here. common hearing loss 2.9 54 Chapter 2 The Head and Neck

Goldenhar Syndrome Cogan Syndrome (Oculo-Auriculo-Vertebral Syndrome) Cogan syndrome is a rare disease of unknown origin Goldenhar syndrome is a congenital disorder related to characterized by nonsyphilitic interstitial keratitis with a group of congenital diseases known as “the hemifa- cochleovestibular defects causing sensorineural hear- cial microsomia spectrum.” These diseases are charac- ing loss. Interstitial keratitis is an infectious, chronic, terized by unilateral or bilateral and often asymmetrical nonulcerative infl ammation of the cornea with neovas- abnormalities of the fi rst and second branchial arch cularization. derivatives with facial asymmetry. The disorder is considered to be an autoimmune Most cases are sporadic and affect one side of the disease. The autoimmune origin theory is supported face only. by the development of generalized vasculitis affect- Goldenhar syndrome is characterized by the following ing the heart coronaries, aorta, and brain vessels in facial features (Fig. 2.9.2): chronic stages of the disease that respond to steroid Unilateral or bilateral external ear atresia (microtia). therapy. Unilateral or bilateral mandibular hypoplasia. The disease affects adults between 20 and 40 years Unilateral or bilateral maxillary fl attening. of age, although it can also affect children in rare Epibulbar dermoid: is a benign, white–yellow, or cases. pinkish tumor located on the cornea and the sclera in Patients with Cogan syndrome present with bilat- the temporal quadrants of the eye (characteristic and eral, rapidly progressing hearing loss with tinnitus often specifi c feature of this disease). combined with vertigo, dizziness, or ataxia. The diagnosis is made based on the clinical combination of eye abnormalities and cochleovestibular disease. Cogan syndrome is classifi ed according to its ocular manifestations into two types: Typical Cogan syndrome: the disease causes nonsyph- Fig. 2.9.2. Illustration ilitic interstitial keratitis (affects the cornea only). shows the typical facial features of Goldenhar Atypical Cogan syndrome: the disease affects the syndrome. Note the right whole globe, presenting with episcleritis, uveitis, unilateral hypoplasia of the and conjunctivitis. mandible, the small right maxilla compared to the left Systemic manifestations of the disease occur in up to one (unilateral hypoplasia), 70% of the patients and include fever, malaise, arthral- the small deformed ear on the right side, and the gias, and weight loss. soft-tissue lesion seen in the Cogan syndrome causes acute autoimmune labryn- right eye (epibulbar thitis, which later leads to diffuse fi brosis, cochlear dermoid) atrophy, and calcifi cations causing permanent hearing loss. The patient may need cochlear implantation.

Signs on Petrous Bone CT Signs on Petrous Bone CT The scan reveals unilateral or bilateral external auditory canal atresia. The cochlea may show signs of thickening, internal soft-tissue Contracted tympanic cavity and oval window atresia may be density (ﬁ brosis), and in advanced stages cochlear sclerosis seen. (Fig. 2.9.3). 2.9 Hearing Loss Syndromes 55

For Further Reading CNS

1. Lee D et al. Waardenburg syndrome, clinical photographs. Otolaryngol Head Neck Surg 1996;114:166–167

2. Rarey KE et al. Intralabyrinthine osteogenesis in Cogan's Head and Neck syndrome. Am J Otolaryngol 1986;4:387–390 3. Oysu C et al. Temporal bone imaging fi ndings in Waardenburg's syndrome. Int J Pediatr Otorhinolaryngol 2001;58:215–221 4. Robson CD. Congenital hearing impairment. Pediatr Radiol 2006;36: 309–324 5. Espeso A et al. The diagnosis of hearing loss in children: Common presentations and investigations. Curr Paediatr Phakomatoses Musculoskeletal System Abdomen and Pelvis and Heart Chest 2006;16:484–488 6. Phelps PD et al. Radiological malformations of the ear in Pendred syndrome. Clin Radiol 1998;53:268–273 Fig. 2.9.3. Coronal petrous bone CT illustration shows thicken- 7. Ozluk A et al. Carcinomas of the thyroid and breast associ- ing and sclerosis of the cochlea (arrowhead ), an advanced stage ated with Pendred's syndrome: Report of a case. Surg Today, of Cogan syndrome Jpn J Surg 1998;28:673–674 8. Thomas P. Goldenhar syndrome and hemifacial microsomia: Observations on three patients. Eur J Pediatr 1980;133: Signs on MRI 287–292 9. Reddy MVV et al. Facio-auricular vertebral syndrome – A In active stage of the disease, the membranous labyrinth case report. Indian J Hum Genet 2005;11(3):156–158 10. Olfat M et al. Cogan's syndrome in childhood. Rheumatol shows enhancement and high signal intensity on postcontrast Int 2001;20:246–249 T1-weighted images due to infl ammation (labyrinthitis) 11. Baumann A et al. Cogan's syndrome: Clinical evolution of (Fig. 2.9.4a). deafness and vertigo in three patients. Eur Arch Otorhino- In advanced stages, a hypointense signal is seen in the laryngol 2005;262:45–49 12. Im GJ et al. Side selection for cochlear implantation in a membranous labyrinth on both T2- and T1-weighted case of Cogan's syndrome. J Laryngol Otology, 2008;122(3): postcontrast images due to calcifi cation and fi brosis 310–313 (Fig. 2.9.4b). 13. Kothari PR et al. ABCD syndrome revisited. Indian J Hum Genet 2006;12(3):144–145

a b

Fig. 2.9.4. Axial T1- and T2-weighted MR illustrations show b Illustration representing a noncontrast-enhanced T2-weighted different stages of the vestibular changes in Cogan syndrome. image showing loss of the normal ﬂ uid signal within the vesti- a Illustration representing a postcontrast T1-weighted image bule due to ﬁ brosis and sclerosis (open arrowhead) showing enhanced vestibule due to labyrinthitis (arrowhead). 56 Chapter 2 The Head and Neck

2.10 cotympanic artery,” which is a remnant of the Petrous Bone Vascular Anomalies embryologic “hyoid artery.” The caroticotympanic artery anastomoses over the cochlear promontory with another artery called the “inferior tympanic artery,” a branch of the ascending pharyngeal artery. Congenital vascular anomalies affecting the petrous Both arteries supply portions of the medial wall of bone can be asymptomatic or can result in pulsatile the tympanic cavity. Aberrant ICA represents an tinnitus. Tinnitus is an auditory sensation perceived in enlarged inferior tympanic artery anastomosing with the absence of external stimuli. It is described as buzz- an enlarged caroticotympanic artery (persistent ing, ringing, or humming. Pulsatle tinnitus is deﬁ ned hyoid artery) with underdevelopment of the cervical as tinnitus that follows the patient's pulse. The most portion of the ICA. common petrous bone vascular anomalies causing pul- The Bony Dehiscence Theory: This is a rare situa- satile tinnitus are the aberrant internal carotid artery, tion characterized by dehiscence of the carotid plate high jugular bulb, and persistent stapedial artery. causing the ICA to herniate inside the middle ear cavity. It is seen on MRI or angiography as a “later- ally displaced” ICA. Aberrant Internal Carotid Artery Clinically, the lesion can be asymptomatic or accompanied by pulsatile tinnitus and conductive The normal carotid artery courses inside the petrous hearing loss. It can be mistaken with glomus tympan- bone in its carotid canal before entering the middle icum or high jugular bulb on otoscopic examination. cranial fossa. Aberrant internal carotid artery (ICA) is a rare condition characterized by presence of the ICA inside the middle (tympanic) ear cavity (Fig. 2.10.1). Signs on Petrous Bone CT The condition is explained by two theories: The Alternate Blood Flow Theory: Normally, the The ICA is seen inside the middle ear cavity with no bony plate ICA inside its canal is separated from the middle ear separating it from the middle ear cavity (Fig. 2.10.2). cavity via the carotid plate, a bony covering that is less than 0.5 mm in thickness. This plate is perfo- rated by a small branch of the ICA called the “caroti- High Jugular Bulb

The jugular bulb is the continuation link between the sigmoid sinus and the internal jugular vein. It lies in the jugular fossa, an oval hollowed area at the internal and inferior surface of the petrous pyramid. The dome of the jugular bulb lies at the ﬂ oor of the middle ear cavity, at the level of the hypotympanum. High jugular bulb is a condition characterized by protrusion of the jugular bulb inside the middle ear cavity, commonly due to hypotympanum bone dehiscence (Fig. 2.10.3). The jugular bulb is said to be high if it projects above the bony annulus or the basal turn of the cochlea. The incidence of high jugular bulb is 5% of the gen- Fig. 2.10.1. Illustration shows aberrant course of the internal eral population; bilateral incidence is found in up to carotid artery inside the middle ear cavity 16% of cases. CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 57

) arrowhead 2.10 2.10 Petrous Bone Anomalies Vascular Axial bone-window petrous bone CT shows bone petrous bone CT shows Axial bone-window Persistence of the stapedial arteryPersistence after birth can be Persistent Stapedial Artery Stapedial Persistent stapedial artery anomaly Persistent is a rare vascular The that can present in adulthood with pulsatile tinnitus. circulation stapedial artery is part of the embryonic fetal If the fetal arteryof the head and neck region. persists after birth, the middle meningeal artery not will and its arterial territorydevelop, the will be supplied by stapedial and the ophthalmic arteries. an aberrant or accompanied by an isolated anomaly 21 as 13, 15, and ICA. It can be seen in cases of trisomy disease of the bone. as Paget’s well Fig. 2.10.4. 2.10.4. Fig. ( the jugular bulb dehiscence over ciency (dehiscence) of ciency ) and ). Note the arrow Axial Illustration shows bone defi Illustration shows cult to differentiate high jugular bulb from glo- high jugular bulb from cult to differentiate arrowhead Clinically, it can be asymptomatic in most cases, or it can be asymptomatic in most cases, or Clinically, Signs on Petrous Bone CT Signs on Petrous uid density projecting inside the a mass with a fl scan shows The middle ear cavity with hypotympanum bone dehiscence 2.10.4). (Fig. Fig. 2.10.2. 2.10.2. Fig. bone petrous bone-window aberrant internalCT shows carotid artery inside the on the left middle ear cavity side ( plate on intact carotid bony the right side ( compare it with the left side compare it with the left accompanied by pulastile tinnitus. Conductive hearing pulastile tinnitus. Conductive accompanied by the tympanic loss can occur if the bulb encroaches over it membrane or the ossicles. On otoscopic examination, is diffi mus tympanicum or aberrant ICA. Fig. 2.10.3. 2.10.3. Fig. the hypotympanum with projection of the jugular bulb inside the with projection of the jugular bulb inside the hypotympanum of the basal turn of the cochlea at the level middle ear cavity (high jugular bulb) 58 Chapter 2 The Head and Neck

For Further Reading Signs on Petrous Bone CT

1. Schwartz JD et al. Aberrant internal carotid artery lying A mass in the mesotympanum lying near the stapes, which within the middle ear, High resolution CT diagnosis and enhances in an arterial fashion after contrast material differential diagnosis. Neuroradiology 1985;27:322–326 injection. The key for diagnosis is the relationship of the artery 2. Sauvaget E et al. Aberrant internal carotid artery in the tem- to the stapes (Fig. 2.10.5). poral bone, imaging ﬁ ndings and management. Arch Oto- laryngol Head neck Surg 2006;132(1):86–91 Foramen spinosum will be absent due to the absence of the 3. Lo WWM. Aberrant carotid artery: Radiologic diagnosis middle meningeal artery (Fig. 2.10.6). with emphasis on high-resolution computed tomography. Radiographics 1985;5(6):985–993 4. Davidson HC. Imaging of the temporal bone. Neuroimag Clin N Am 2004;14:721–760 5. Roche PH et al. High jugular bulb in the translabryrinthine approach to the cerebellopontine angle: Anatomical consid- erations and surgical management. Acta Neurochir (Wien) 2006;148:415–420 6. Ozturkcan S et al. Surgical treatment of the high jugular bulb by compressing sinus sigmoideus: Two cases. Eur Arch Otorhinolaryngol 2008;265(8):987–991. doi 10.1007/s00405- 007-0545-0 7. Lo WWM et al. High-Resolution CT of the jugular foramen: Anatomy and vascular variants and anomalies. Radiology 1984;150:743–747 8. Thiers FA et al. Persistent stapedial artery: CT ﬁ ndings. Am J Neuroradiol 2000;21:1551–1554 9. Branstetter BF IV. The radiologic evaluation of tinnitus. Eur Radiol 2006;16:2792–2802

Fig. 2.10.5. Coronal noncontrast-enhanced petrous bone CT illustration shows the persistent stapedial artery with its close relationship to the stapes (arrowhead). Note the origin of the artery from the carotid canal (arrow)

Fig. 2.10.6. Axial base of the skull CT illustration shows absence of the foramen spinosum on the right side (circle), a typical ﬁ nding with persistent stapedial artery CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 59

2.11 Orbital Anomalies Anomalies Orbital 2.11 is a condition is a condition Retinochoroidal colo- is a syndrome characterized a localized, infl ammatory expansion infl a localized, Axial orbital CT illustration shows cystic expansion expansion cystic Axial orbital CT illustration shows occurs in the inferior aspect of the eye near the occurs in the inferior aspect of the eye erential diagnosis of optic nerve coloboma There is cystic the optic nerve, of which is isodense expansion There 2.11.2). humor (Fig. with the vitreous and is continuous of the optic nervecation in cases of nerve can be seen Calcifi atrophy. not be found. or may may Microphthalmia Staphyloma: characteristic It lacks the fundoscopic (ectasia) of the globe. of the optic nerve coloboma. feature with cyst: Microphthalmos of the globe with gross malformation severe by characterized of the the size forming a cyst can exceed dilatation that scleral the cyst on CT An important is that globe. neck is feature smaller than the cyst coloboma). itself (not as wide as the Optic nerve coloboma is usually associated with Optic nerve is usually coloboma

Signs on Orbital CT Diﬀ by microcephaly, coloboma of the iris and optic disc, microcephaly, by strabismus, and mental retardation. coloboma: Retinochoroidal boma optic disc. It is bilateral in up to 60% of cases. Megarbane syndrome: Megarbane other anomalies such as optic nerve atrophy, frontos- nerve such as optic other anomalies atrophy, craniosynostosis. encephalocele, and phenoidal

Fig. 2.11.2. 2.11.2. Fig. of the right optic disc (optic disc coloboma) rst year of life rst year oor, and is sur- oor, eld disturbance and sometimes Illustration shows the typical fundoscopic appear- Illustration shows The disease is diagnosed in the ﬁ nition for coloboma is absence of some ocular tis- nition for coloboma is absence of some The disease has an autosomal dominant mode of The disease has an autosomal dominant The defect occurs at the optic disc. On fundoscopy, fundoscopy, The defect occurs at the optic disc. On of the optic disc, and excavation there is enlargement in its ﬂ has pale glial tissue which choroidal tis- an annulus of pigmented rounded by coloboma This appearance is typical for optic disc sue. can be normal or eye The rest of the 2.11.1). (Fig. microphthalmic. aligned are not properly due to strabismus (the eyes with each others) and poor vision. Optic disc coloboma (morning glory syndrome): Optic disc coloboma (morning

ssure. Orbital Anomalies Orbital Coloboma is a rare congenital orbital anomaly charac- congenital orbital anomaly Coloboma is a rare herniation of the retina through a choroidal terized by Another pouch within the eye. defect, creating a cystic defi with blindness. Coloboma intraocular due to malclosure of the fetal sue, usually fi inheritance. Three types of colobomas are found: Orbital anomalies are usually seen in infants and chil- usually Orbital anomalies are present rare. Children usually dren, and are generally fi in life with visual early 2.11 Fig. 2.11.1 Fig. ance of the optic disc coloboma “morning glory syndrome” 60 Chapter 2 The Head and Neck

occurs in the posterior aspect of the globe at the tem- Signs on Orbital CT poral side of the optic disc. Staphyloma is commonly associated with congeni- The scan shows a small globe (microphthalmia) with a tal myopia, a condition characterized by painless bulg- retroocular cyst that is connected to the vitreous humor ing eye and amblyopia (poor vision in a physically inferiorly. normal eye).

Fuch’s coloboma (tilted disc syndrome) Fuch’s coloboma is a rare congenital malformation character- Signs on Orbital CT ized by tilting of the optic disc in any direction, with myopia, and minor dilatation of the inferionasal area The scan shows a focal posterior or anterior bulge within the eye, of the globe due to scleral thinning. and an area of thinning or absence of the scleral–uveal rim The disease is bilateral in 80% of patients. (Fig. 2.11.4). There is no contrast enhancement after contrast There is an association between Fuch’s coloboma material injection. and craniopharyngioma and craniosynostosis.

Signs on Orbital CT

Moderate to severe hypoplasia of the choroids, retina, and sclera. Focal dilatation of the inferionasal posterior wall of the globe, with oblique insertion of the optic nerve and the retinal arteries (Fig. 2.11.3).

Fig. 2.11.4. Axial orbital CT illustration shows thinning of the scleral-uveal region of the right globe, representing a classic sign of staphyloma (arrowhead)

Coats Disease

Fig. 2.11.3. Axial orbital CT illustration shows bilateral, abnor- Coats disease is a rare congenital, idiopathic, nonfamil- mal, tilted insertion of the optic nerves into the orbit, a typical sign ial disease characterized by an abnormal blood–retinal of “tilted disc syndrome” (arrowheads) barrier of the retinal arteries, resulting in leakage of yellowish exudates rich in cholesterol crystals into the ves- Staphyloma sel wall. Weakening of the blood vessel wall causes the formation of telangiectases (chronic dilatation of groups Staphyloma is a condition characterized by bulging of of capillaries), aneurysms, and subretinal leakage the uvea into a thinned and stretched sclera. It commonly (Fig. 2.11.5), all of which lead to retinal detachment. CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 61

- arrow- 2.11 Orbital Anomalies Anomalies Orbital 2.11 Axial orbital CT illustration shows bilateral calcifi Axial orbital CT illustration shows Axial orbital CT illustration shows homogeneously homogeneously Axial orbital CT illustration shows ) The mean age of presentation is about 12 years of 12 years The mean age of presentation is about Signs on CT of the optic disc cation calcifi bilateral scan shows The 2.11.7). (Fig. eld defects in 80% of cases and with migraine-like nding in Coats disease Fig. 2.11.7. 2.11.7. Fig. cation of the optic nerves in optic disc Drusen disease ( heads age (hyaline proteins take time to deposit and calcify). proteins take age (hyaline acci- The disease is familial, and sometimes discovered Up on ophthalmoscopic or CT examinations. dentally present with visual to 70% of cases are bilateral. Patients fi headache in up to 30% of cases. Fig. 2.11.6. 2.11.6. Fig. a mass lesion, a typical left globe with absence of hyperdense fi ex when one shines a when ex cations (very commonly seen commonly cations (very Illustration shows the typical fundoscopic appear- the typical Illustration shows population. cation. It occurs in about 1% of the retinoblastoma is very common). retinoblastoma stages. in advanced detachment retinal or incomplete Partial hyperdense on CT, and hyperintense on T1-weighted and T1-weighted on and hyperintense on CT, hyperdense and hemorrhage exudates due to MR images T2-weighted 2.11.6). (Fig. as presents mass (retinoblastoma of intraocular Absence mass). intraocular in cation (calcifi cation calcifi of intraocular Absence The vitreous humor in the aff is homogeneously ected eye in the aff humor vitreous The

The main indication for orbital CT is to differenti- The main indication for orbital CT is to The mean age of presentation is between 3 and 9 The mean age of presentation is between and affects The disease is unilateral in 80% of cases, and The main signs of the disease are strabismus Signs on CT and MRI Optic disc drusen is a rare disease characterized by surface material on or near the deposition of hyaline-like resulting in optic disc of the optic disc, subsequently calcifi Optic Disc Drusen bright light on the pupil; it normally appears red). bright light on the pupil; it normally sear- chronic Coats disease by from ate retinoblastoma ching for intraocular calcifi years of age. years men in 70% of cases. pupillary refl (white leukokoria in retinoblastoma). Fig. 2.11.5. 2.11.5. Fig. ance of Coats disease. Note the intravitreous hemorrhage and ance of Coats disease. Note the intravitreous and hyperin- result in a hyperdense which exodates, yellowish MR images tense appearance of the globe on both CT and 62 Chapter 2 The Head and Neck

Persistent Hyperplastic Primary Vitreous

In the embryo, the primary vitreous occupies the space between the lens and the retina, and it is supplied by a branch from the posterior ophthalmic artery called “the hyaloid artery” in the third week of gestation. Later in life, the primary vitreous is replaced by a secondary vitreous and the hyaloid artery regresses by the third tri- mester. Persistent hyperplastic primary vitreous (PHPV) represents a condition characterized by persistent proliferation of the primary vitreous due to persistence of the hyaloid artery supplying it (Fig. 2.11.8). PHPV is a disease of infants, and occurs in a unilateral eye. The infant presents with micropthalmia and leukokoria (white papillary reﬂ ex). PHPV is the sec- Fig. 2.11.8. Illustration shows the fundoscopic appearance of the persistent hyaloids artery in PHPV (open arrowhead) ond most common cause of leukokoria after retinoblastoma.

Signs on Orbital CT

The aff ected eye is microphthalmic (Fig. 2.11.9). Generalized increase in the vitreous density in the aff ected eye (Fig. 2.11.9). An irregular mass with posterior vitreous extensions present at the area of the lens (Fig. 2.11.9). The lens is deformed and misshaped, with no signs of calcifi cation. The lens may be replaced by fat (Fig. 2.11.8). Retinal detachment may be present. Enhancement of the abnormal vitreous mass after contrast material administration. Triangular, cylindrical, or tubular intraventral densities Fig. 2.11.9. Axial orbital CT illustration shows the typical fi nd- representing remnant of the primary vitreous (Fig. 2.11.9). ings in PHPV. Note the small size of the eye (white arrow), the irregular mass with posterior vitreous extensions present at the area of the lens (open arrow), the deformed lens (white arrowhead), and the tubular intraventral densities representing remnants of the primary vitreous (open arrowhead). Also, note the hyperdense vitreous humor of the affected right globe compared to the normal left globe CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 63

ndings. ndings. cation of 2.11 Orbital Anomalies Anomalies Orbital 2.11 ndings. Radiology 1994;191:59–61 ndings. Radiology nerve 1983;148:137 ed optic drusen. (PHPV): Role of computed tomography and magnetic tomography reso- of computed Role (PHPV): Am 1987;25(4):683–692 Radiol Clin North nance. 2008;14(1):27–29 colobomas, morning glory anomaly, and colobomatous cyst. cyst. and colobomatous morning glory anomaly, colobomas, Am 1987;25(4):693–699 Radiol Clin North fi and fundoscopic MR, CT, syndrome: disk” “tilted 1999;20:1750–1751 Am J Neuroradiol 2004;20:87–90 Child Nerv Syst locele. 2006;148:1123–1125 (Wien) Neurochir Acta the orbit. CT fi syndrome): roimag Clin N Am 2004;14:809–825 Clin N roimag Radiology 2001;221:64–69 globe. fected calcifi 9. Mafee MF et al. Persistent hyperplastic primary vitreous Persistent MF et al. Mafee 9. Genet J Hum Indian syndrome. Megarbane CA et al. Okay 10. For Further Reading Further For 1. Mafee MF et al. Computed tomography ofnerve optic tomography Computed al. MF et Mafee 1. the to related pseudohemianopia Bitemporal L et al. 2. Manfre glory Morning encepha- and basal syndrome CS et al. Chen 3. cyst of and colobomatous Micropthalmia Doglietto F et al. 4. Optic (morning nerve glory coloboma et al. BL Murphy 5. MR imaging Neu- of the globe nerve. and optic Belden CJ. 6. - of the af Smaller volume disease: Coats P et al. Galluzzi 7. tomographic identifi Computed H et al. Ramirez 8. broblastic overgrowth of a overgrowth broblastic ndings plus history of prematurity and oxygen Axial orbital CT illustration shows bilateral micro- Axial orbital CT illustration shows ndings to PHPV, but characteristically affects affects but characteristically ndings to PHPV, The disease has similar manifestations and radio- The disease has similar The disease has a correlation with high oxygen Diagnostic criteria: care unit and oxygen therapy. care unit and oxygen 2.11.10). Bilateral disease with small globe (Fig. History of prematurity with admission to intensive History of prematurity with admission to intensive

Fig. 2.11.10. 2.11.10. Fig. phthalmia with masses seen around the lens in the same pattern These fi as PHPV. of prematurity are diagnostic criteria for retinopathy therapy Retinopathy of prematurity is a disease that occurs in disease that occurs of prematurity is a Retinopathy ves- of blood babies due to abnormalpremature growth and fi sels within the retina, Retinopathy of Prematurity (Retrolental (Retrolental of Prematurity Retinopathy Fibroplasias) sheath behind the lens as a conse- persistent vascular can progress The disease birth.quence of premature resulting in complete weeks within a few rapidly blindness. fi logical due to prematurity. therapy both eyes bilaterally and symmetrically (whereas PHPV (whereas and symmetrically bilaterally both eyes occurs in bothWhen PHPV a single globe). affects to differentiate with which criterion globes, the only of prematurity is the history of the it from retinopathy patient. 64 Chapter 2 The Head and Neck

2.12 ear cavity) causing intracranial extension of the lesion. Congenital Cholesteatoma Patients with acquired cholesteatoma usually present with conductive hearing loss and ear discharge. In contrast, patients with congenital cholesteatoma present with conductive hearing loss and a whitish mass behind Cholesteatoma is a mass of abnormal squamous epi- an intact tympanic membrane (seen with an otoscope). thelium (ectopic skin) found inside the middle ear cav- Congenital cholesteatoma has the same pathological ity. When cholesteatoma occurs inside the brain, it is and radiological features as acquired cholesteatoma, referred to as “epidermoid cyst.” except that it usually occurs in young patients with no Up to 98% of cholesteatomas are acquired, only 2% history of ear infections. are congenital. Congenital cholesteatoma can arise anywhere within Acquired cholesteatoma arises as a complication of the petrous bone, but it is commonly found at the cer- recurrent, chronic otitis media. It originates commonly ebellopontine angle, the petrous apex, the geniculate from the sinus tympani, or Prussak's space, which is ganglion region, and the tympanic mastoid cavity. the lateral space between the scutum and the ossicles. Congenital cholesteatoma can be mistaken with Cholesteatoma commonly erodes the scutum ﬁ rst, “cholesterol granuloma” when it affects the petrous affecting the integrity of the tympanic membrane. It apex; differentiation between both lesions can be can also erode the tegmen tympani (roof of the middle achieved by MRI.

Fig. 2.12.1. Coronal and axial postcontrast petrous CT sections in a 9-year-old patient with congenital cholesteatoma. In a, there is an isodense opacity fi lling the middle ear cavity (black arrowhead), with an intact tympanic membrane (open arrowhead). In b, the cholesteatoma is seen fi lling the adetus ad antrum and the mastoid antrum (black arrow). In c, the middle ear cavity and the mastoid air cells are fully fi lled by the cholesteatoma (thick black arrow). Notice lack of enhancement and bone erosions in all sections CNS Head and Neck Chest and Heart Abdomen and Pelvis Musculoskeletal System Phakomatoses 65

stula. stula. 2.12 Congenital Cholesteatoma Congenital 2.12 ), and completely destroying the ossicles destroying ), and completely Coronal postcontrast petrous CT section in another Coronal postcontrast petrous CT section in another open arrowhead lling the middle ear cavity, eroding the tegmen tympani eroding the tegmen lling the middle ear cavity, epidural abscess, sinus thrombosis and cavernous fi and cavernous thrombosis sinus abscess, epidural Neurosurg Rev 1996;19:189–191 Rev Neurosurg 2004;14:721–727 Am Clin N For Further Reading Further For 1. with spontaneous cholesteatoma Congenital A et al. Gok Fig. 2.12.3. 2.12.3. Fig. cholestea- large patient with acquired cholesteatoma. Notice the toma fi violating the integrity of the tympanic mem- arrowhead), (white brane ( 2. Neuroimag bone. Imaging of the temporal CH. Davidson (vanished within the mass) (vanished ) black arrow black stula” ( stula” Coronal postcontrast petrous CT section in a patient and hemorrhagic material commonly found at the petrous the petrous found at commonly and hemorrhagic material T2 signal and high T1 low gives Cholesteatoma apex. high signal gives granuloma while cholesterol intensities, of hemorrhagic–fatty its mix due to all sequences in intensity content. middle ear cavity with opacifi ed mastoid air cells (Fig. 2.12.1). (Fig. cells air ed mastoid with opacifi middle ear cavity administra- material contrast after lesions do not enhance The tion (diagnostic). scutum erosions) Signs of bone destruction be seen (e.g., may 2.12.2 and 2.12.3). (Figs. ammatory mass with fatty infl is an granuloma Cholesterol An isodense, nondependent soft-tissue opacity nondependent seen within the An isodense,

Signs on Petrous Bone CT and MR Bone Signs on Petrous Fig. 2.12.2. 2.12.2. Fig. with acquired cholesteatoma. Notice the bony erosion of the teg- with acquired cholesteatoma. Notice the bony into the middle of the cholesteatoma men tympani with extension Notice the lack of enhance- arrowhead). intracranial fossa (white The cholesteatoma also destruction of the ossicles. ment and sever ﬁ the cochlea forming “labyrinthine invades