Ectopic thyroid tissue in adrenal gland, case report and review of literature

Abstract

Ectopic thyroid tissue is a rare pathological finding bellow the diaphragm and extremely rare finding is ectopic thyroid tissue in the adrenal gland (ETTAG). Thyroid tissue can be located anywhere along the way of embryological migration pathway of thyroglossal duct. In most cases of ectopic thyroid tissue, it is located in the neck. Here we present a case of 29 years old patient that was laparoscopically operated because of adrenal incidentaloma which showed 28 mm in maximal diameter on MRI. The patient had normal adrenal function. Pathohistological finding confirmed ETTAG. Follicular cells express TTF-1, Thyroglobulin, PAX8, and cytokeratin 7, and lack expression of calretinin. This is the 15th such case described in literature. Women are much more affected than men (14:1), and it usually presents in the fifth decade (mean age 49). In all cases ETTAG was composed of normal follicular cells, and C cells were not found. Review of the literature reveals that adrenal ectopic thyroid tissue is almost always cystic, and has distinctive pathologic features. The most important thing is that ETTAG must be distinguished from metastatic deposits from thyroid gland carcinoma. Our patient had normal thyroid function, without any nodules in thyroid gland. We report the youngest patient with ectopic thyroid tissue located in the adrenal gland.