BACKGROUND: Pheochromocytoma is a rare catecholamine-producing tumor with an estimated incidence of less than 0.1% in the global population. We present a case of cystic pheochromocytoma that was diagnosed as an incidental finding. The patient presented with abdominal pain and had a history of hypertension.

CASE REPORT: A 64-year-old man with hypertension presented with a clinical history of intermittent abdominal pain for one year. He denied sweating, palpitations, headache or back pain. He was found to have an elevated blood pressure of 170/90 and no palpable abdominal mass. Contrast-enhanced computed tomography (CT) imaging of the abdomen and pelvis were performed that showed cystic mass measuring 9 cm in diameter arising from the left adrenal gland with contrast-enhancing mural nodules. Magnetic resonance imaging (MRI) confirmed the cystic nature of the mass. Laboratory analysis showed an elevated plasma normetanephrine (NMN) of 1,087 pg/ml and metanephrine (MN) of 372 pg/ml; 24-hour urine showed elevated levels of NMN and MN, 3,002 mg/24 h and 1,596 mg/24 h, respectively. Given the laboratory and radiologic findings, a diagnosis of cystic pheochromocytoma was made. After controlling blood pressure with the alpha-blocker, doxazosin, the patient was hydrated and scheduled for an elective adrenalectomy. The histopathology of the excised adrenal gland was consistent with a cystic pheochromocytoma.

CONCLUSIONS: Cystic pheochromocytoma is a very rare tumor that may present without symptoms. The clinical course of cystic pheochromocytoma is similar to that of solid pheochromocytoma. Early surgical intervention is recommended, following blood pressure control with an alpha-blocker, and adequate hydration.

Keywords: Metanephrine, Normetanephrine, Pheochromocytoma