A rare case of malignant paraganglioma of urinary bladder

Paraganglioma of the urinary bladder is a rare pathologic entity with no definitive histological, immunohistochemical or molecular features to determine its malignant potential. Malignancy is essentially determined by the presence of deep local invasion, invasion of adjacent structures and lymph node or distant metastases. So far, up to 180 cases of paraganglioma have been reported, with <30 being malignant. A 50-year-old male presented with painless hematuria for 6 months. Cystoscopic biopsy of the bladder mass was given as invasive urothelial carcinoma. Patient underwent radical cystectomy with pelvic lymphadenectomy. The gross morphological brown discoloration of mass on formalin fixation was suspicious of paraganglioma and was confirmed on immunohistochemistry. The diagnosis of malignant paraganglioma was made based on regional lymph node metastases. We describe a rare case of a patient with malignant urinary bladder paraganglioma with main differential diagnostic considerations on the histomorphology.