A Case of Adrenocortical Oncocytoma / 대한내분비학회지

ABSTRACT

Oncocytomas are neoplasms, histologically are composed of epithelial cells, with abundant, acidophilic and granular cytoplasm. Electron microscopic studies of oncocytomas have shown that the cytoplasm of oncocytes is packed with mitochondria. The adrenal gland is a very rare anatomical site for oncocytomas, and to the best of our knowledge, only thirty-six cases of adrenal oncocytomas have been described. Herein, a case of a large adrenal mass in a forty-year-old man, which was incidentally detected by abdominal ultrasonography, is presented. This patient demonstrated no clinical manifestation associated with adrenal hyperfunction. Hormonal studies showed no abnormal findings, except for a mild elevation of the 24-hour urinary VMA level. Abdominal computed tomography with enhancement revealed a large, well-defined left adrenal mass, measuring 5.0x.2 x.0cm. The patient underwent a left adrenalectomy, and a light microscopic examination confirmed an adrenocortical oncocytoma, with characteristic oncocytes and polygonal, abundant, eosinophilic and granular cytoplasm. The tumor cells were positive for cytokeratin and vimentin as well as S-100, but negative for chromogranin on immunohistochemical staining. An electron microscopic examination demonstrated closely packed mitochondria, containing intramitochondrial inclusions. After surgery, there was no evidence of a recurrent or distant metastatic disease at the 5 month follow-up. In summary, an extremely rare case of a man with an adrenocortical oncocytoma is reported, which was confirmed by histological examinations, including electron microscopy.