Pheochromocytoma of the urinary bladder: report of 2 cases and review of literature.

Pheochromocytoma of the urinary bladder is a rare neoplasm of the chromaffin tissue of the sympathetic nervous system within the layers of the bladder wall. Approximately 220 cases have been reported in literature. It accounts for less than 0.06% of all urinary bladder tumors and less than 1% of all pheochromocytomas. Females are affected more frequently and it is more common between the second to fourth decades of life. The diagnosis is strongly based on the clinical symptoms related to catecholamine hypersecretion. In some cases however, the tumor is hormonally inactive and may go undetected for years. The cytologic features of benign and malignant tumors overlap and thus there are no reliable features of malignancy. Nevertheless the prognosis seems to be better for patients with superficial tumors comparing to patients with invasive tumors, found in 5-10% of cases. In the majority of cases the treatment of choice is surgical resection. For metastatic tumors, chemotherapy and radiotherapy seem to be effective. The authors present two new cases of pheochromocytoma of the urinary bladder. The presenting symptom was painless hematuria. Both patients had well-controlled blood pressure and none of the characteristic symptoms of pheochromocytoma. The authors discuss the difficulties in diagnosis and treatment and briefly review literature.