Ectopic Thyroid - Two Case Reports DGM Akaiduzzaman1, Md

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Bangladesh J Otorhinolaryngol 2012; 18(2): 193-199 Case Report

Ectopic thyroid - two case reports DGM Akaiduzzaman1, Md. Zahedul Alam2, Manilal Aich1

Abstract: Bachground: Ectopic thyroid is a rare entity resulting from maldescent of the thyroid gland & can be found anywhere between the foramen cecum & the normal pretracheal position of the thyroid gland, as well as in distant places such as the mediastinum and the subdiaphragmatic organs. Although most cases are asymptomatic, obstructive symptoms may appear. Any disease affecting the thyroid gland may also involve the ectopic thyroid, including malignancy. Hypothyroidism is frequent but hyperthyroidism is an exceptionally rare finding. The clinician must distinguish between ectopic thyroid and metastatic deposits emerging from an orthotopic gland, as well as other benign or malignant masses. Thyroid scintigraphy plays the most important role in diagnosing ectopy, but ultrasonography contributes as well. Treatment is indicated in the presence of symptoms & consists initially of full replacement thyroid hormone therapy. Severe or unresponsive cases require excision. Case reports: We present here two case reports & review of the literature. Conclusion: This review provides current understanding about the wide clinical spectrum of this rare condition, optimal diagnostic approach, differential diagnosis, and management strategies. Key words: Thyroid; ectopic

Introduction: >90% of ectopic thyroid. Extralingual thyroid Ectopic thyroid is a rare developmental tissue is commonly located in the anterior abnormality resulting from aberrant cervical area along the path of the embryogenesis of the thyroid gland during thyroglossal duct2. Other rare locations of its passage from the floor of the primitive ectopic thyroid are the submandibular foregut to its final pre-tracheal position1. region, trachea, esophagus, mediastinum, Lingual site is the most common cause heart, lung, abdomen etc3. Its prevalence is about 1 per 100 000–300 1. Assistant Professor of ENT, Sir Salimullah 000 people, rising to 1 per 4000–8000 patients Medical College, Dhaka, Bangladesh. with thyroid disease1. However, in autopsy 2. Professor of ENT, Sir Salimullah Medical studies, the prevalence ranges from 7 to College, Dhaka, Bangladesh. 10%4. More than 440 cases have been Address of Correspondence: Dr. DGM reported to date. In 70–90% of cases, it is Akaiduzzaman, Assistant Professor of ENT, Sir 1,4,5 Salimullah Medical College (SSMC), Dhaka, the only thyroid tissue present . Ectopic Bangladesh. E-mail: mamunmail24@ thyroid is most common in females, gmail.com especially in populations of Asian origin5. It ENT 18 (2), 2012 194

Bangladesh J Otorhinolaryngol Vol. 18, No. 2, October 2012 may occur at any age, from 5 months to 40 gland not visualized in thyroid area. There is years, but it is most common at younger a focal area of radiotracer concentration in ages. the oral cavity-suggesting thyroid tissue in ectopic position at the tongue base. she was Case report 1: started on thyroid hormone replacement A 15-year-old female presented with the therapy, levothyroxine, 50 ug daily & history of not gaining height since her earlier hypothyroidism including the size of ectopic operation in the neck 8 years back in 2003 thyroid is reducing in size. for thyroglossal duct cyst. Upon referral to the ENT clinic she was seen in the ENT Case report 2: department of SSMC, Dhaka in May 2011. A 13-year-old male child presented to the The patient gives the history of slow thought ENT outdoor with a painless mass in the & coarse dry skin but has normal anterior neck that had been present for at intelligence & menstruation. Oropharyngeal least 8 years & is gradually increasing in examination showed a spherical mass at the size. Upon referral to the otolaryngology back of the tongue but covered with intact clinic the patient was found to have a mucosa measuring 3-2-2 cm. Thyroid smooth, soft to firm, mobile, 3 cm mass in hormone study reveals elevated TSH 43.54 the anterior neck above the hyoid region. mIU/L but with normal serum T3 4 pml/L & This mass elevated with swallowing but

T4 9.3 pml/L level suggestive of movement on tongue protrusion was difficult hypothyroidism. Thyroid ultrasonogram to evaluate. A presumptive diagnosis of report shows no thyroid tissue in thyroid bed, thyroglossal duct cyst (TGDC) was made. Thyroid spect scan by Tc99 shows thyroid Fine needle aspiration biopsy of the neck

Figure 1: First case with Spect CT (a & b)

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Figure 2: Second case with Spect CT (a & b) mass was performed in Rajshahi & was Discussion: consistent with TGDC and negative for A larger study of 49 cases of ectopic thyroid malignancy. He was otherwise completely in Korea found lingual thyroid in 23 patients, well and has normal intelligence. sublingual thyroid in 17 patients, combined Ultrasonogram reveals no thyroid tissue in type in 7 patients and an intratracheal thyroid thyroid position. Radioisotope scan shows in one patient. Only four cases had thyroid a focal increased radiotracer concentration in orthotopic position, and 62% in the oral cavity but no uptake in the thyroid demonstrated hypothyroidism5. We report bed suggestive of ectopic thyroid tissue in two patients, one with lingual and another is sublingual region & the midline neck mass sublingual and both of them showed absent was in fact the only functioning thyroid thyroid in normal thyroid bed & tissue. demonstrated hypothyroidism. We found lingual thyroid in female and sublingual Spect CT shows increased radiotracer thyroid in male. concentration in submental region corresponds to the area in between the Clinical presentation of ectopic thyroid mandible and hyoid bone a bit right from tissue: the midline below the level of the tongue. Lingual thyroid: Thyroid hormone study reveals elevated Lingual thyroid is the most frequent cause TSH 28.98 mIU/L but with normal serum of ectopic thyroid, accounting for about 90% T3 2.34pml/L & T4 57.54pml/L level of the reported cases6. In 70-75% of cases, suggestive of hypothyroidism. He was lingual thyroid is the only thyroid tissue started on thyroid hormone replacement present as it is found in our case. Our therapy, levothyroxine, 50 ug daily & the patient gives the history of excision of size of the ectopic thyroid is reducing in thyroglossal cyst 8 years back & now she size. presented with lingual thyroid along with 195 ENT 18 (2), 2012 196

Bangladesh J Otorhinolaryngol Vol. 18, No. 2, October 2012 symptoms of hypothyroidism in the absence shape, color, consistency, vascularity and of orthotopic thyroid gland. Related papers mucosal continuity, and are of minor of thyroglossal cyst excision is not importance in making a diagnosis. avialabe. Treatment of thyroglossal cyst Physical examination is usually sufficient involves Sistrunk’s operation & include for diagnosis, although CT or nuclear excision of the body of the hyoid and en imaging may provide additional block dissection in the line of descent of information. the throid gland as far as the foramen 7 caecum . Probably the tract was not Extralingual ectopic thyroid tissue: excised as far as the foramen cecum in Extralingual ectopic thyroid most commonly our patient. In terms of thyroid function, located in a midline position above or below most patients with lingual thyroid present the hyoid bone, the region of the with hypothyroidism, Hyperthyroidism is thyroglossal duct cyst. We report a case extremely rare. found above the hyoid bone (Sublingual). Normal glands hypertrophy during puberty, It must be differentiated from thyroglossal menstruation and pregnancy. Relative duct cyst, because it is usually located in deficiency of thyroid hormones with these the same anatomic position13 & frequently events will also cause the ectopic thyroid represents the only source of thyroid to enlarge and become symptomatic. tissue, removal of which has definite Onset of symptoms of lingual thyroid is physiologic as well as possible often associated with these events8. This medicolegal implications. To prevent total situation is more common in women thyroid ablation, a thyroid scan or (seven times)9. We found it in female ultrasound examination must be performed patient as is found in other study in our in all cases of thyroglossal duct cyst before country10. its removal so as to be certain that a normal The diagnosis is usually made by the thyroid gland is present. Our patient was incidental discovery of a mass on the back initially diagnosed as thyroglossal duct of the tongue in an asymptomatic patient. cyst on FNAC but on USG, Thyroid scan The mass may enlarge and cause a mild & Spect scan it was proved to be ectopic sensation of fullness in the throat to thyroid. dysphagia, dysphonia, dyspnea, or a Hypothyroidism is commonly present as in sensation of choking, cough, snoring, sleep our case because of the absence of a normal apnea11, and, in more severe cases, thyroid gland in most instances. An respiratory obstruction and hemorrhage12. enlarging mass commonly occurs during In our patient there is no obstructive infancy, childhood or later life. Our patient symptoms. presented at 13 years of age. Extralingual On examination a mass is seen in the ectopic thyroid tissue can also undergo the base of the tongue, often visible without same pathological changes as the ectopic the aid of a laryngeal mirror. Its thyroid gland, and can be benign or characteristics are very variable in size, malignant.

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Ectopic thyroid tissue and its clinical presentation14.

Location Symptomatology Age at Thyroidal diagnosis status Lingual Dysphagia, dysphonia, stomatolalia, 0–83 Usually cough, sensation of foreign body, snoring hypothyroid, less and sleep apnea, respiratory obstruction, often euthyroid and hemorrhage Asymptomatic Submandibular Palpable, mobile, usually painless mass 4–81 Euthyroid Thyroglossal Asymptomatic 4–75 Hypothyroid or duct cyst euthyroid Intratracheal Dyspnea, cough, difficulty in swallowing, 30–50 Euthyroid hemoptysis, and stridor Asymptomatic lung, and Intra- Dry cough, dyspnea, and hemoptysis 40–77 Euthyroid thoracic (med- iastinal, heart) Asymptomatic Struma ovarii Usually asymptomatic 45 Euthyroid, hyperthyroid in 5–15% Lower abdominal pain, palpable lower abdominal mass, and abnormal vaginal bleeding Adrenal glands Asymptomatic (incidental finding) 50–67 Euthyroid Duodenum, Asymptomatic (incidental finding) 50–63 Euthyroid pancreas and intestine Rarely abdominal pain Dual ectopy Midline neck swelling or asymptomatic 4–45 Euthyroid or (usually lingual hypothyroid and subhyoid)

Investigations: Thyroid hormone tests may reveal the thyroid Scintigraphy, using Tc-99m, I-131, or I-123, function status. is the most important diagnostic tool to CT and MRI are also useful modalities in detect ectopic thyroid tissue and shows the cases when radioiodine uptake by normal absence or presence of thyroid in its normal thyroid gland masks the uptake of the ectopic location. Thyroid scan can also unmask thyroid tissue, especially in the midline. additional sites of thyroid tissue. Color Doppler US, computed tomography (CT), and Fine needle aspiration cytology (FNAC) magnetic resonance imaging (MRI), may help helps in confirming the diagnosis of ectopic in designating the extension and location of thyroid. It is the only modality to ectopic tissue, thus contributing to a better differentiate between a benign and a pre-surgical evaluation of these cases 4,11,15. malignant lesion4.

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Differential diagnosis: failure of suppression therapy to reduce its Ectopic thyroid tissue can pose difficult size, ulceration, hemorrhage and suspicion diagnostic and management problem. of malignancy. Ectopic thyroid tissue should be considered Medical treatment: in the diagnosis of a cervical mass even in For mild symptoms and hypothyroid states, the presence of a eutopic thyroid gland. The levothyroxine replacement therapy may be clinician should always take into account the effective, leading to considerable mass potential of this rare entity and differentiate it 4,11,12,15 from other masses in the neck and distant reduction . Ablation with radioactive sites. iodine has been recommended. Its long-term carcinogenic effects & potential deleterious In general, differential diagnosis depends on effect on the gonads and other organs11 render the location. Lingual and submandibular it unsuitable for use with these predominantly thyroid must be differentiated from adenomas young to middle-aged patients. and cysts in the midline, including angiomas, fibromas, lymphangiomas, lipomas, salivary Surgical treatment: gland tumors, thyroglossal duct cysts, midline Patients with severe symptoms, or who do branchial cysts, and epidermal or sebaceous not respond to medical therapy will require cysts11,15. Thyroid cancer metastases should complete excision of the lesion. Inability to always be excluded, as these can manifest exclude carcinoma, for example a sudden or as an ectopic thyroid tissue6. Lingual thyroid is an important cause of a mass on the recent enlargement with no obvious posterior third of the tongue & should be precipitating factor, is an absolute indication. differentiated from other swellings at the base Several surgical approaches for lingual thyroid of the tongue, such as hypertropic lingual have been described, such as the transoral tonsil, vallecular cyst, and mucous retention route and the transhyoid, suprahyoid, or cyst15. lateral pharyngotomy. Trans-oral approach has been most popular in the past16. Management: Dissection of an extensive lesion may still There is no consensus about the be difficult. Lateral pharyngotomy provides the management due to the rarity of this clinical most satisfactory approach in terms of entity. Most authors agree that surgical exposure and dissection. The former is usually treatment of ectopic thyroid in the neck preferred for small lesions since it does not (mainly lingual, sublingual, submandibular, affect deeper structures; thus complications and lateral cervical) depends on size and local are avoided. The latter approach with or symptoms (airway obstruction, dysphagia, without preoperative tracheotomy is chosen and dysphonia), as well as on other for larger masses providing better control of parameters, such as patient’s age, functional bleeding11,16. thyroid status, and complications of the mass (ulceration, bleeding, cystic degeneration, or References: malignancy)4,11,12,15. The usual treatment 1. Babazade F, Mortazavi H, Jalalian H & of ectopic thyroid is thyroid hormone therapy Shahvali E. Thyroid tissue as a to suppress the ectopic thyroid and reduce submandibular mass: a case report. its size. Only rarely is surgical excision Journal of Oral Science 2009; 51: 655– necessary. Indications for extirpation include 657.

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