Ectopic Thyroid in the Adrenal Presenting as an Adrenal Incidentaloma

ABSTRACT

Adrenal incidentalomas are clinical dilemmas for the clinicians. The work up, to differentiate between malignant and benign lesions, and hyperfunctioning and nonfunctioning lesions is mandatory before the consideration of surgical resection. Ectopic thyroid tissue located in the adrenal gland (ETTAG) is a very rare condition. We report a case of ETTAG presenting with adrenal incidentaloma. A 57-year-old woman was admitted with incidental right adrenal mass. Hormone evaluation showed no hormonal activity. Magnetic resonance imaging revealed a 20x17 mm lobulated solid mass, which contained millimetric hypointense nodular areas consistent with calcifications. Loss of signal intensity on out-of-phase could not be evaluated because of the calcifications. Right adrenalectomy was performed to establish the histopathological diagnosis and to rule out malignancy. Histopathological diagnosis revealed ETTAG. Her medical history was positive for multinodular goiter and bilateral subtotal thyroidectomy 32 years ago. Thyroid ultrasonography showed residual thyroid tissue in both the right and left lobes, and colloid thyroid nodules. Fine needle aspiration biopsy from the nodules revealed benign nodules. The patient has been followed up for six years, and no change in thyroid nodule sizes and no evidence of metastatic foci have been detected. ETTAG would be considered in the differential diagnosis of adrenal mass showing no hormonal activity, especially when magnetic resonance images are not consistent with adrenal adenoma. Long follow-up duration of this case suggests that it was a benign condition.