Functioning adrenocortical oncocytoma: a case report and review of the literature.

Adrenocortical oncocytoma is exceptionally rare. Most of these tumors are benign and nonfunctioning. We report a case of functioning adrenocortical oncocytoma located in the right adrenal gland in a 53-year-old woman who presented with Cushing's syndrome. The tumor was small, with exclusively oncocytic histologic features. A discussion of this case and a review of the literature on this entity is presented.