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THYROID HEMIAGENESIS ACCOMPANYING A THYROGLOSSAL DUCT CYST

Posted Tue, 09/08/2009 - 08:08 by mailpkd
Images

Transverse ultrasound image of the thyroid gland.

Normal right lobe, paramedian thyroid cyst

Nodule in right lobe of thyroid, left lobe hemiagenesis

VRT image


Clinical History:

A 20yrs girl presented to surgical outpatient department with history of noticing painless, slowly growing swelling of insidious onset over few months in the anterior aspect of neck on right side.
Clinical diagnosis of solitary thyroid nodule was made and patient investigated.
Complete hemogram, thyroid function tests, RFT and ECG performed- Reports within normal limits.
FNAC of the lesion revealed colloid goiter.
Patient was then referred for USG examination.


Findings:

USG revealed absence of isthmus and left lobe of thyroid gland with enlarged right lobe and a clear cyst on the left side. No mural nodule noted within the cyst.
Plain CT performed subsequently confirms ultrasound findings and no ectopic thyroid tissue is visualized.


Diagnosis:

HEMIAGENESIS OF THYROID GLAND WITH THYROGLOSSAL CYST


Discussion:

Thyroglossal duct cysts (TDCs) are the most common congenital neck anomaly. It is thought to represent segments of the duct that fail to regress and consequently differentiate into epithelial-lined cysts. TDCs develop anywhere along the course of the duct remnant, from the base of the tongue to the suprasternal region. Cysts located near the foramen caecum are lined by stratified squamous epithelium, whereas cysts located near the thyroid gland are lined by cells similar to thyroidal acinar epithelium.
Thyroid hemiagenesis is a failure of the embryologic development of a lobe of the thyroid gland. The thyroid gland begins to develop as a median thickening of endoderm on the floor of the pharynx between the first and second pharyngeal pouches. This area later invaginates to form the median diverticulum, This diverticulum grows caudally as a bifurcating tubular duct, from which the isthmus and the lateral lobes of the thyroid are developed. Thyroid agenesis may be complete, unilateral or isthmic. Congenital hemiagenesis is thought to be the rarest developmental anomaly of the thyroid gland. Left lobe was absent in 80% of the cases and the right lobe was absent in 20% of the cases (a left to right hemiagenesis ratio of 4:1).Females accounted for 75% and males accounted for 25% of the cases, giving a female to male ratio of 3:1.
Combination of thyroid hemiagenesis and thyroglossal cyst is yet rarer then TDC and hemiagenesis considered separately.


References / Suggested Reading:

1. Koeller KK, Alamo L, Adair CF, Smirniotopoulos JG. Congenital cystic masses of the neck: radiologic-pathologic correlation. Radiographics 1999;19:121–146
2. Reede DL, Bergeron RT, Som PM. CT of thyroglossal duct cysts. Radiology 1985;157:121–125
3. Thyroglossal duct cysts: variability of sonographic findings. AJR Am J Roentgenol1994;163:1475-1477
4. Okstad S, Mair MB, Sundsfjord JA, et al. Ectopic thyroid tissue in the head and neck. J Otolaryngol 1986;15:152-155
5. Warwick R, editor. Williams PL. Gray’s Anatomy, 36th edition. Edinburgh: Churchill Livingstone,1980;198.
6. McHenry CR, Walfish PG, Rosen IB et al. Congenital thyroid
hemiagenesis. Am Surg 61: 634-638. 1995.


Author

Ranjeet Jagdale,MD., Paresh Desai. MD

staff Radiologist

Goa Medical College - Goa University INDIA

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Sat, 09/12/2009 - 00:45
#1
Vikram Dogra
jdogra's picture
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Joined: 05/23/2007
Excellent case

This is a very unique case. Thank you for your submission.

Dr. Vikram Singh Dogra

Professor of Radiology, Urology & BME
Associate Chair for Education and Research.
Department of Imaging Sciences
University of Rochester School of Medicine

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