|Year : 2017 | Volume
| Issue : 2 | Page : 103-105
Dual Thyroid Ectopia with Changes of Colloid Goitre – A Rare Case Report
Ankita Malik, Prashant Gupta, Shubdha Sagar, Sonal Saran
Department of Radio-diagnosis, Imaging & Interventional Radiology, N.S.C.B. Subharti Medical College, Swami Vivekananda Subharti University, Subhartipuram, Meerut, U.P., India
|Date of Web Publication||28-Jun-2017|
108, Chanakyapuri, Shastri Nagar, Meerut-250004, U.P.
Source of Support: None, Conflict of Interest: None
Ectopic thyroid is a rare entity, and simultaneous presence of ectopic thyroid gland at two different sites is even rarer with only 42 reported cases in world literature. We report a case of a 14-year-old girl with dual thyroid ectopia at the base of tongue and at the level of hyoid bone. The patient presented with a midline swelling in the neck with hypothyroidism. High-resolution ultrasonography of the neck revealed absence of thyroid tissue in its normal location and presence of thyroid tissue with changes of adenomatous colloid goiter at the level of hyoid bone. A technetium 99-m pertechnetate scan revealed two hyperfunctioning foci of ectopic thyroid tissue − one at the base of the tongue and other at the level of the hyoid bone.
Keywords: Dual ectopic thyroid, lingual thyroid, ultrasonography
|How to cite this article:|
Malik A, Gupta P, Sagar S, Saran S. Dual Thyroid Ectopia with Changes of Colloid Goitre – A Rare Case Report. MAMC J Med Sci 2017;3:103-5
|How to cite this URL:|
Malik A, Gupta P, Sagar S, Saran S. Dual Thyroid Ectopia with Changes of Colloid Goitre – A Rare Case Report. MAMC J Med Sci [serial online] 2017 [cited 2018 Jul 22];3:103-5. Available from: http://www.mamcjms.in/text.asp?2017/3/2/103/209024
| Introduction|| |
Ectopic thyroid means the presence of thyroid gland or tissue out of its normal anatomical pretracheal location. The most common presentation of ectopic thyroid gland is lingual thyroid. Ninety percent of ectopic thyroid cases are found at the base of the tongue. The remaining 10% are located in the suprahyoid, infrahyoid, and prelaryngeal regions along the thyroglossal line, beginning from the tongue base to the normal gland location; aberrant thyroid tissue can sometimes be seen in the mediastinal region, esophagus, larynx, gallbladder, duodenum, lung, and heart. We report a case of a 14-year-old girl with dual ectopic thyroid.
A 14-year-old girl presented to the department of the radiodiagnosis and imaging with midline anterior neck swelling in the region of hyoid. Palpation revealed a well defined, smooth mass moving with deglutition in midline. The normal thyroid gland was not palpable. No other mass or lymphadenopathy was found in the rest of the neck region. Her thyroid function tests showed primary hypothyroidism with TSH 6.23 mIU/L (0.25–5.0), T3 2.11 nmol/L (0.92–2.33), and T4 128.46 nmol/L (60–120).
High-resolution sonography of neck at the site of the swelling revealed a well defined, echogenic, solid mass at the level of hyoid bone with presence of internal vascularity [[Figure 1]a and [Figure 1]b]. There was absence of thyroid gland in its normal location [Figure 2]. Fine needle aspiration cytology (FNAC) of the neck mass showed sheets of follicular epithelial cells with macrophages in a background of blood mixed with thick and thin colloid suggesting features of colloid goiter with cystic changes. A technetium (99mTc) pertechnetate thyroid scan revealed uptake in lingual region and at the level of the hyoid bone consistent with dual ectopic thyroid [Figure 3]. On the basis of the above findings, diagnosis of dual ectopic thyroid tissue in the lingual and hyoid region in midline was established with absence of ectopic thyroid. She has since been put on levothyroxine daily and is under a regular follow-up [Figure 4].
|Figure 1: High resolution sonography showing ectopic thyroid tissue at the level of the hyoid bone with changes of colloid goitre|
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|Figure 2: High resolution sonography showing ectopic thyroid tissue at the level of the hyoid bone with changes of colloid goiter and vascularity|
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|Figure 3: High resolution sonography in the same patient showing absence of any thyroid tissue in its normal location|
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|Figure 4: 99mTc pertechnetate thyroid scintigraphy revealed presence of ectopic thyroid tissue at the level of hyoid and at the base of tongue|
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| Discussion|| |
Ectopic thyroid is a congenital aberration, resulting from abnormal migration of the thyroid gland. Simultaneous presence of ectopic thyroid at two different sites is an unusual entity, and the exact incidence is not known. The prevalence of ectopic thyroid tissue ranges between 7 and 10%. Lingual thyroid is the most common ectopic thyroid accounting for 90% of all cases with a prevalence between 1 : 100,000 and 1 : 300,000 and a clinical incidence between 1 : 4000 and 1 : 10,000.
The exact pathogenesis of dual ectopic thyroid is still not known; however, genetic factors have been implicated with thyroid gland morphogenesis and differentiation. Mutation in genes has not been associated with human thyroid ectopy so far. The different pathologies that affect normal thyroid gland can also affect ectopic thyroid tissue.
Ectopic thyroid is more commonly encountered in women, with a female-to-male ratio of 4:1. It can present at any age but is usually encountered during the second decade of life. Approximately 70% of the cases with dual ectopic thyroid do not have any thyroid tissue in its normal location. In the present case, there was no thyroid gland at its anatomical position; however, the patient was hypothyroid.
Majority of the cases of ectopic thyroid gland are asymptomatic. Symptoms may appear following enlargement of thyroid gland during periods of stress. They can vary according to location of the ectopic thyroid tissue and include dysphonia, dysphagia, dyspnea, neck mass, and altered thyroid status. Familial dual ectopic thyroids with perihyoid ectopic thyroid and lingual thyroid have also been described. Malignant transformation of ectopic thyroid tissue is very rare. Most of such cases are papillary carcinomas that should be identified from the metastases of a usual thyroid carcinoma.
High-resolution sonography and neck computerized tomography (CT) are important modalities in forming a differential diagnosis for midline neck swelling. Thyroid scan with 99mTc pertechnetate is important for diagnosing ectopic thyroid tissue and also detect presence of other sites of thyroid tissue. Treatment may be conservative with substitutive hormone treatment in patients with mild symptoms and surgery for patients showing clinical signs of upper airway obstruction or with a lesion showing signs of infection or malignant degeneration.
| Conclusion|| |
Ectopic thyroid is a rare entity but must always be considered in the differential diagnosis of a midline neck swelling. The possibility of another ectopic focus should always be kept in mind when an ectopic thyroid is encountered and must be evaluated. Proper diagnosis can help in avoiding unnecessary surgery in an asymptomatic ectopic thyroid gland as it may be the only functioning thyroid tissue in the body.
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Conflict of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]