[A Case of Retroperitoneal Tumor in the Adrenal Area Turned Out to Be Schwannoma Mimicking an Adrenal Malignant Tumor].

A 76-year-old woman was found to have bilateral suprarenal tumors, 6.5 cm in diameter on the right side, and 2.4 cm in diameter on the left side, by ultrasonography, computed tomography, and magnetic resonance imaging. Strong accumulation of fluorodeoxyglucose in these tumors was found on positron emission tomography. Since it mimicked an adrenal malignant tumor, we performed right adrenalectomy. The pathological diagnosis of the removed mass was benign schwannoma, consistent of the Antoni type A. The left suprarenal tumor was not removed and she has been followed up for 18 months without any recurrence or tumor increase.