[Asymptomatic unilateral adrenal medullary hyperplasia with a cyst: case report].

A 45-year-old man was admitted with asymptomatic adrenal tumor. He had normal plasma and urinary catecholamine levels. The swelling of right gland was detected by CT scan and MRI. Selective venous samplings were performed and the level of catecholamine into the right adrenal vein were much higher than that into the left one. On July 15th, 1993, a right adrenalectomy was carried out and the right adrenal gland with a large cyst could be found. The ratio of cortical area to medullary area was about 4:1. Therefore, it was pathologically diagnosed as adrenal medullary hyperplasia with a cyst. There are relatively few reports of adrenal medullary hyperplasia. Before the operation, the patients were mostly diagnosed as pheochromocytoma by the results of laboratory studies and their symptoms. The condition of this disease is usually bilateral and often associated with type II multiple endocrine neoplasia (MEN II). We describe a case of asymptomatic unilateral adrenal medullary hyperplasia.