Oncocytoma of the adrenal gland medulla.

We report an unprecedented case of an oncocytoma of the adrenal gland medulla in a 61-year-old woman. The patient presented with right flank pain and hematuria. Computed tomographic studies revealed a right adrenal gland mass that measured 2 cm, which was subsequently excised laparoscopically. Grossly, the tumor in the medulla measured 1.9 × 1.2 cm, weighed 5 g, and had a solid tan-brown cut surface. Histologically, it consisted of large tumor cells containing eosinophilic granular cytoplasm arranged in trabecular and nodular patterns. Electron microscopy revealed closely packed mitochondria in the cytoplasm of almost all tumor cells. The tumor cells were immunohistochemically positive for vimentin. The patient resumed usual activities 2 weeks after surgery, and at 6-month follow-up, she is doing well.