Clinicopathological study of pheochromocytoma of the urinary bladder: Immunohistochemical, flow cytometric and ultrastructural findings with review of the literature

Pheochromocytomas usually arise from the adrenal medulla but may also arise from the carotid body, the retroperitoneum, the urinary bladder, and other locations. We report three cases of pheochromocytoma of the urinary bladde r with clinicopathological, immunohistochemical, flow cytometric, and ultra structural findings. Case 1, a 13-year-old boy presented with hematuria. He underwent partial cystectomy, 31 years rater he presented with a tumor in the thoracic vertebra. Case 2, a 35-year-old woman presented with headache, nausea, vomiting, palpitations, and diaphoresis on evacuation. She underwe nt total cystectomy and regional lymph adenectomy. She survived for 10 year s without recurrence or metastasis; however, she died from another disease. Case 3, a 31-year-old man presented with dysuria. He underwent total cyste ctomy and regional lymph adenectomy. The tumor metastasized to the lymph no des, and the patient died after 4 years. The urinary bladder tumors in thes e three cases protruded into the lumen and invaded deeper than the middle o f the muscle layer. The tumor of the urinary bladder, metastatic lymph node s, and thoracic vertebra showed alveolar and trabecular patterns, and tumor cells were surrounded by capillaries. The tumor cells were moderate in siz e with ovoid nuclei and abundant eosinophilic cytoplasm that contained acid ophilic granules reactive to Grimelius stain. Vascular invasion was observe d in cases 1 and 2. Immunohistochemically, tumor cells showed reactivity fo r chromogranin, Leu 7, and S-100 protein. In each of the three cases, the D NA ploidy pattern on flow cytometry was aneuploid. Ultrastructural examinat ion revealed several neurosecretory granules, rough endoplasmic reticulum, and a few mitochondria within the cytoplasm. It is difficult to determine w hether pheochromocytoma of the urinary bladder is malignant on the basis of histological, immunohistochemical, and flow cytometric findings. Long-term follow up is necessary.