Adrenal medullary hyperplasia mimicking pheochromocytoma.

A 59-year-old woman, a known case of hypertension, was incidentally diagnosed with a large right-sided adrenal mass. Investigations for a functional adrenal lesion resulted in very high preoperative norepinephrine levels. A right adrenalectomy was performed. Histology showed adrenal medullary hyperplasia (AMH). AMH is a rare diagnosis and its incidence is poorly documented in the literature. This is a benign entity which resembles pheochromocytoma (PCC) in both clinical and biochemical manner. AMH is usually bilateral and may occur in isolation or in association with PCC. In fact, some authors consider it to be a precursor to PCC. Thus, these patients need long-term follow-up in view of the risk of development of PCC later.