Granular cell tumor (Abrikossoff tumor) of the thyroid gland

Abstract Only 4 cases of granular cell tumor of the thyroid have been previously reported in the English literature. We report herein the fifth case of this uncommon neoplasm and the first one affecting a male patient. The tumor was well circumscribed and located to the left thyroid lobe, near the isthmus. Histologically, the tumor was composed of large, rounded, granular eosinophilic cells that were immunohistochemically positive for S-100, calretinin, and PGP9.5 and negative for cytokeratin AE1-3, TTF-1, and thyroglobulin.