Ectopic Thyroid Tissue in the Adrenal Gland

Abstract

Foci of ectopic thyroid tissue are uncommon. Most sites of thyroid ectopia are confined to the neck region. The presence of ectopic thyroid tissue outside the migration pathway of the primitive thyroid in other locations is exceptional. Given that any disease of the thyroid gland may also affect ectopic thyroid tissue, pathologists has to recognize benign or malignant conditions that may develop in the ectopic focus. We present the case of a 32-year-old woman with ectopic thyroid parenchyma in the adrenal gland. Clinically, postoperative thyroid ultrasound echography and computed tomography scans did not reveal any thyroid tumor. The ectopic tissue was a cyst bordered by mature follicular thyroid structures and was histologically benign, without the molecular alterations associated with malignant tumors of follicular cell derivation (BRAFV600E, N-RAS, H-RAS, K-RAS). Review of the literature reveals that adrenal ectopic thyroid tissue is nearly always cystic and has distinctive pathologic features.