We report the first case of a primary adrenal natural killer (NK)/T-cell nasal type lymphoma in adults. The patient presented with an enlarging left adrenal mass and the initial concern was for adrenocortical carcinoma. Surgical resection revealed NK/T-cell lymphoma. Rapid recurrence in the contralateral adrenal gland was treated with a single cycle of chemotherapy before he died due to infectious complications and progressive disease. This case demonstrates the aggressive presentation of a novel subset of primary adrenal lymphoma that should be considered in the differential diagnosis of a rapidly enlarging adrenal mass.