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• Suprahyoid region: from base (BOS) to hyoid • Excluding orbit (O), sinunasal cavity (S/N) and oral cavity (OC)

Suprahyoid spaces: and principle pathologies Sofie Van Cauter, MD PhD

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Superficial fascia (between dermis and deep layer): superficial musculo‐aponeurotic system MULTIPLE SPACES Deep fascia: Superficial layer Middle layer Deep layer

Fascial layers cannot be seen on imaging

Courtesy of Dr Jeffrey Hocking, Radiopaedia.org, rID: 43811 34

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MULTIPLE SPACES ANATOMY: SOME CONSIDERATIONS

• Pharyngeal mucosal space (oro‐ /nasopharynx)

• (prestyloid parapharyngeal space) • Carotid space (poststyloid parapharyngeal space)

• Masticator space () • Parotid space • Submandibular Oropharyngeal isthmus: • Sublingual ‐ Junction of the hard and soft • Buccal ‐ Anterior tonsillar pillars – palatoglossal arches/muscles ‐ Line of the circumvallate papillae

• (proper / ) • Perivertebral space (prevertebral/paraspinal)

5 principal spaces 2 posterior midline spaces 56

PATHOLOGY SPACE SPECIFIC DIFFERENTIAL DIAGNOSIS

INFECTIOUS/INFLAMMATORY ONCOLOGY Tonsillitis – Peritonsillar abscess Nasopharyngeal carcinoma Odontogenic abscess Tonsillar carcinoma (Sialo)adenitis Lymphoma Retropharyngeal edema/abscess Neurogenic tumours Paraganglioma tumours

VASCULAR CONGENITAL Jugular vein trombosis First branchial cleft cyst

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PHARYNGEAL MUCOSAL SPACE PHARYNGEAL MUCOSAL SPACE

T(h)ornwald(t) cyst: Lymphoid hyperplasia: Tonsillar abscess: ‐ Pharyngeal mucosal space – nasopharynx ‐ Pharyngeal mucosal space – nasopharynx ‐ Extent: tonsillar ‐> peritonsillar  PPS/SMS Contents: Mucosa, lymphatic ring, minor salivary ‐ Benign midline cyst ‐ Young adults ‐ Look at lingual/palatine tonils –FOM glands, constrictor muscles ‐ Developmental (4%): retraction of the notochord ‐ Look at the lingual and palatine tonils ‐ Airway status! ‐ P/ infection (rare) ‐ DD. Lymphoma –NPC ‐ Lemierre syndrome Extent: skull base to ‐ No erosion – Symmetric – Inflammatory septa Naso/oropharynx

Importance: Broad pathology (infectious –Inflammatory – Neoplastic)

Displacement: Invades laterally into the parapharyngeal space Invades posteriorly in the retropharyngeal space

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PHARYNGEAL MUCOSAL SPACE PHARYNGEAL MUCOSAL SPACE

SCC Nasopharyngeal ca: SCC Tonsillar ca: Lymphoma: ‐ Large masses versus small ‐ Asymmetry in adenoids ‐ From nodal tissue ( cervical lymph nodes, palatine/ , adenoi) ‐ Invasion skull base –retro‐obstructive fluid in mastoid ‐ Nodes in level 2! ‐ Extranodal locations ( orbits, sinonasal region, salivary glands, , subarachnoid space) ‐ Retropharyngeal nodes ‐ DDx: SCCa

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PARAPHARYNGEAL SPACE PARAPHARYNGEAL SPACE

Prestyloid PPS Primary lesions: rare! Salivary gland tumour Contents: Fat, V3 branches, Internal , Schwannoma aspecnding pharyngeal artery, venous plexus Second branchial cleft cyst (atypical location)

Extent: skull base to hyoid bone Secondary lesions: displacement patterns Connection to inferiorly Masticator space postermedially Importance: Parotid space anteromedially Easily identified Pharyngeal mucosal space posterolaterally Displacement helsp define location of larger SHN Carotid space anteriorly lesions Retropharyngeal space anterolaterally

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PARAPHARYNGEAL SPACE PARAPHARYNGEAL SPACE

Displacemen t from the parotid space

Case 1: Venolymphatic malformation (courtesy A. Mancuso) Case 2: Schwannoma (J Surg Case Rep, Volume 2020, Issue 3, March 2020)

Displacement from the PMS Courtesy A. Mancuso Displacement from the carotid space 15 16

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CAROTID SPACE CAROTID SPACE

Poststyloid PPS

Contents: , internal jugular vein, Vascular lesions: CN IX, X, XI and XII, sympathetic plexus, lymph nodes Jugular vein trombosis

Extent: jugular foramen to aortic arch Pseudoaneurysm Dissection Fascia: all three layers Fibromuscular dysplasia

Importance: Neoplastic lesions Conduit skull base to Paragangliomas Nerve sheet tumours

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CAROTID SPACE CAROTID SPACE

Case 1: tonsillitis with IJV thrombosis Paragangliomas –glomus tumours Nerve sheet tumours

< 0,5% tumours H&N More common Vascular lesions: Neural crest cells Jugular vein trombosis Sporadic and familial Sporadic and familial ‐ Rare Carotid sheet – middle ear CN IX, X (also IH), XI and XII ‐ IV drug abuse, hypercoagulable state, infections or Carotid body paraganglioma –glomus caroticum MRI: Homo‐/heterogenuous trauma ‐ Near bifurcation enhancement, no flow voids, ‐ Lemierre syndrome ‐ Most common (60‐70% of total) cystic changes ‐ CT/MRI: look along the course of the vessels Case 2: tonsillitis with IJV thrombosis Glomus vagale tumor ‐ Associated with n. X. ‐ Extremely rare ‐ Level C1

MRI: “Salt and pepper” appearance Flow voids! Intense enhancement

DSA ‐ ocreotide scan

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CAROTID SPACE CAROTID SPACE

November 2019 June 2020

Case 1: Glomus vagale Case 2: Glomus caroticum

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CAROTID SPACE CAROTID SPACE

Case 2: Glomus caroticum Case 3: Sympathetic chain schwannoma (Arch Otolaryngol Head Neck Surg 2007; 133(7): 662‐667)

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MASTICATOR SPACE MASTICATOR SPACE

Contents: , TMJ, pterygoid venous plexus, Contents: mandible, TMJ, pterygoid venous plexus, NV3, masticator muscles NV3, masticator muscles 1. 1. 1. 1. Extent: above zygoma to mandible Extent: above zygoma to mandible 4. 3. 3. 4. (Temporal fossa <‐> Infratemporal fossa) (Temporal fossa <‐> Infratemporal fossa)

Importance: Perineural tumour spread Odotogenic abscess Rhandomyosarcoma 2. 2. 1. Masseter muscle Displacement: * 2. Temporal muscle 4. 3. Pushes posteromedially into PPS * 4. 4. Lateral pterygpid muscle

1. 1. 3. 3. 1. * Zygomatic arc 1.  Temporal fossa

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MASTICATOR SPACE PAROTID SPACE

Odontogenic abscess: Perineural tumour spread: Rhabdomyosarcoma: ‐ Tooth 37/38/47/48: find the offending tooth! ‐ SCC skin/oropharyngeal region ‐ < 20 years old ‐ Thick enhancing fluid collection ‐ Thickening and contrast enhancement ‐ H&N 50% RMS Contents: , n.VII, parotid nodes, ‐ Mandible!  subperiostal abscess. periostal reaction ‐ Foramen ovale ‐> intracranial ‐ CT: mandibular destruction retromandibular vein, ‐ MRI: heterogenuous lesion ‐ hemorraghe Extent: Lateral skull base to parotid tail

Importance: First branchial cleft cyst Parotid infections (obstructive) Parotid space lesions

Displacement: Pushes anteromedially into PPS

+ 18M Robson Pediatr Radiol 2010 27 28

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PAROTID SPACE RETROPHARYNGEAL SPACE

First brachial cleft cyst: Parotid infections (obstructive): Parotid space lesions: ‐ 7% of branchial cleft anomalies ‐ Swelling, edema, contrast enhancement ‐ 80% benign –most common pleiomorphic adenoma ‐ Type III: periparotid ‐ Periparotitis, abscess ‐ Benign characteristics (FNAC) vs Agressive (parotidectomy) Contents: fat, lymph nodes ‐ Well defined cystic mass +/‐ sinus tract ‐ Ductal obstruction, sialolithiasis ‐ Multiple lesions: lymphoma, HIV, Sjögren, Whartin ‐ Malignant: mucoepidermoid carcinoma, adenoid cystic carcinoma Extent: Skull base to Th4 –diafragm (danger space) ‐ Level 1 and 5 LN! Importance: Infection conduit to mediastinum (DS) Suppurative lymph nodes Adenopathies

Case 1 Pleiomorphic adenoma Retrophar yngeal space

Alar fascia

Case 2 Danger space Adams et al. Insights Imaging 2016 Sjogren Atypical ‐ MEC 29 30

RETROPHARYNGEAL SPACE PERIVERTEBRAL SPACE

Retropharyngeal edema: Suppurative retropharyngeal adenitis: Tumoural adenopathy: ‐ Look for cause ‐ Pediatric ‐ Oral cavity/naso/oropharynx ‐ Edema ⌿ abscess ‐ Pharyngitis ‐ tonsillitis ‐ SCC –pap thyroid ca –NHL Contents: muscles, phrenic nerve, brachial plexus, ‐ NOT a !! ‐ Radiotherapy vertebral artery, spine ‐ < 3 cm  IV AB ‐ Airway! Vessels! Extent: Skull base to Th4 Prevertebral compartment Importance: Longus colli tendinitis ‐ = acute calcific prevertebral tendinitis ‐ Hydroxyapatite deposition in longus colli tendon ‐ Neck pain , fever, odynophagia, dysphagia ‐ Self limited Case 1

Paraspinal compartment Case 2 31 32

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“ Dans les champs de l’observation, le hasard ne favorise ques les esprits préparés” “ Where observation is concerned, chance favours only the prepared mind”

Conclusion Louis Pasteur

• Anatomic spaces  normal structures and pathology in the neck.

• Pharyngeal mucosal space: broad pathology – look for additional findings (nodes –invasion) • Parapharyngeal space: displacement patterns

• Carotid space: glomus tumours versus neurogenic tumours • Masticator space: odontogenic abscess • Parotid space: lesions 80% benign –try to differentiate between benign and aggressive lesions

• Retropharyngeal space: edema! • Paravertebral space: longus colli tendinitis

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Glomus caroticum Glomus vagale Nerve sheet tumour

Level bifurcation Level C1

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