Extra-adrenal Pheochromocytoma of the Urinary Bladder in an Adolescent Female Patient

Pheochromocytoma is a catecholamine-secreting tumor that arises from the medullary chromaffin cells but can rarely be extra-adrenal in origin. We present a case of a 16-year-old female patient with uncontrolled hypertension, despite being on lisinopril and metoprolol, and associated left-sided chest pain, recurrent headaches, and an unintentional weight loss of 10 pounds in one month. Laboratory work-up showed a markedly elevated plasma metanephrine level of 4463.4 pmol/L (normal range <510 pmol/L). Since it is important to find the location, rule out malignant pheochromocytoma, and consider preoperative strategy, imaging studies were performed. Abdominal ultrasound revealed a hypervascular mass in the right adnexa, while an MRI of the abdomen and pelvis identified a lobulated soft tissue mass in the right hemipelvis with diffusion restriction that appeared to be arising from the urinary bladder. Given the clinical presentation, significant elevation in catecholamines, and MRI results, extra-adrenal pheochromocytoma (EAP) was the leading differential diagnosis. Phenoxybenzamine was initiated to control her blood pressure and a partial cystectomy was performed to excise the tumor involving the right posterolateral bladder wall. Histopathological report from urinary bladder tissue biopsy confirmed the diagnosis of EAP. This case highlights a rare and intriguing presentation of EAP arising from the urinary bladder, successfully managed with partial cystectomy.