Adrenal Microcystic Reticular Schwannoma

Abstract

Schwannomas are usually benign tumors, originating from the Schwann cell myelin sheath around the peripheral or cranial nerves. Visceral schwannomas are rare, and less than 60 cases of adrenal schwannomas have been reported. Microcystic/reticular schwannoma (MRS) is the rarest variant of schwannoma and only 2 cases have been reported in the adrenal gland. Here we describe a third case. We describe a case of an adrenal MRS with a comprehensive literature review. The patient was a 69-year-old, Caucasian female with abdominal pain. An abdominal computed tomography scan revealed a solid, lobulated, 78-mm mass of the left adrenal gland. Two inconclusive adrenal biopsies were performed and then she was referred to our tertiary center for further evaluation. No clinical or laboratorial signs of endocrine dysfunction were identified. A positron emission tomography scan with fluorodeoxyglucose showed a single left adrenal hypermetabolic mass (SUVmax = 71.7), suggestive of malignancy. In this context, an open left adrenalectomy was undertaken. The histologic evaluation showed an MRS. Adrenal MRSs are extremely rare tumors. Definitive diagnosis of schwannoma can only be made by surgical excision with histopathologic and immunohistochemical evaluation of the specimen.