Endocrinol Metab.  2012 Sep;27(3):217-221. 10.3803/EnM.2012.27.3.217.

A Case of Ectopic Thyroid Tissue Diagnosed by Fine Needle Aspiration in the Lateral Neck

• Lee KN
• Kim SM
• Choi JH
• Ryu KD
• Kim BW
• Shin MJ
• Kim BH
• Kim IJ

• KMID: 2282405
• DOI: http://doi.org/10.3803/EnM.2012.27.3.217

Abstract

Ectopic thyroid glands generally occur in the midline as a result of abnormal median migration and their presence in lateral to the midline is rare. Embryologically, the thyroid gland is derived from two anlages: a large median endodermal anlage and two lateral anlages. The median anlage produces most of the thyroid parenchyma, whereas the lateral anlage is derived from the fourth pharyngeal pouch and contributes 1-30% of the thyroid weight. In rare cases, failure of the lateral anlage to fuse with the median anlage can result in lateral ectopic thyroid gland. For many years, lateral, aberrant thyroid tissue in adults was a term used almost exclusively for metastatic thyroid carcinoma. However, aberrant, benign ectopic thyroid tissue rarely occurs. We present a 47-year-old man who had incidentally detected mass on the right lateral neck. He was clinically in a euthyroid status and the thyroid function test results were normal as well. Neck ultrasonography revealed a mild diffuse goiter and a 1.22 x 0.65 cm sized ovoid mass like lesion was located in the right level IV of the neck. The result of fine needle aspiration cytology was adenomatous goiter without lymphoid tissue or any malignancy. We rarely report aberrant, benign ectopic thyroid presence as a lateral neck mass.

Keyword

Fine needle aspiration; Neck; Thyroid dysgenesis

MeSH Terms

Adult
Biopsy, Fine-Needle
Endoderm
Goiter
Humans
Lymphoid Tissue
Middle Aged
Neck
Thyroid Dysgenesis
Thyroid Function Tests
Thyroid Gland
Thyroid Neoplasms

Figure

• 

  Fig. 1 Technetium-99m (99mTc) thyroid scan. 99mTc thyroid scan shows mild diffuse enlargement of the thyroid gland. Lateral neck mass was invisible on thyroid scan.

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  Fig. 2 Ultrasonography of thyroid gland. Ultrasonography of thyroid gland shows a 1.22 × 0.65 cm sized ovoid mass like lesion in right level IV (white arrow). (A) Transverse view. (B) Longitudinal view. (C) Color Doppler image shows a mass with peripheral vascularity. (D) Follow-up ultrasonography image shows no significant interval change.

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  Fig. 3 Histologic findings of fine needle aspiration of neck mass. (A) The histologic picture of the aspirated specimen shows clusters of follicular cells and colloid (H&E stain, × 400). (B) The colloid stains blue or purple with Giemsa staining (Giemsa stain, × 400).

• 

  Fig. 4 Follow-up neck computed tomography after 3 years. The 1.1 cm sized mass was located between right internal jugular vein and sternocleidomastoid muscle (red arrow) without evidence of compression to adjacent structures or thrombosis.

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