[A case of pheochromocytoma with a large pseudocyst].

We report a case of pheochromocytoma with a markedly large pseudocyst. A 51-year-old man with the complaint of headache and palpitation was referred to our hospital. Ultrasonography (US) revealed a right adrenal cystic mass. Computerized tomography (CT) and magnetic resonance imaging (MRI) confirmed an adrenal cyst. MRI showed a high intensity mass in both T1 and T2-weighted-images, suggesting an adrenal hemorrhagic cyst. 131I-meta-iodo-benzylguanidine (MIBG) scintigraphy showed a prominent accumulation at the right adrenal lesion. Considering the abnormal elevation of cathecholamines in blood and urine samples, we performed right adrenolectomy with the clinical diagnosis of pheochromocytoma. 131I-MIBG scintigraphy was the most important diagnostic tool in the diagnosis of pheochromocytoma.