Malignant Extra-adrenal Paraganglioma of the Bladder: A Rare Clinical Entity

Bladder paragangliomas are uncommon extra-adrenal neuroendocrine tumors that arise from chromaffin tissue within the bladder wall. Clinical presentation varies from hematuria to catecholamine-related paroxysms, and malignant transformation, although uncommon, carries significant morbidity. We report a 45-year-old woman who presented with painless hematuria. Contrast-enhanced computed tomography (CECT) revealed a 3.6×3 cm lobulated, enhancing posterior bladder wall mass. Transurethral resection of the bladder tumor (TURBT) was performed, and histopathology confirmed paraganglioma. The patient was asymptomatic for six months, when she re-presented with recurrent hematuria and palpitations. Urinary normetanephrines were markedly elevated (3239 μg/24 h; normal 119-451 μg/24 h). 68Ga-DOTANOC positron emission tomography (PET)/CT revealed recurrence with right external iliac nodal metastasis. Following α- and β-blockade, she underwent anterior pelvic exenteration with an ileal conduit. Intraoperative hypertensive crisis (blood pressure (BP) 224/120 mmHg) was managed with nitroglycerin infusion. Histopathology revealed malignant paraganglioma infiltrating perivesical fat (pT3b) with nodal metastasis (pN1). The tumor demonstrated comedo-type necrosis, >250 cells/HPF, atypical mitoses, and Ki-67 index of 40%. The Grading of Adrenal Pheochromocytoma and Paraganglioma (GAPP) score was 9, indicating poorly differentiated high-risk disease. Immunohistochemistry was positive for chromogranin, synaptophysin, S100, and INSM1. Margins were negative. Bladder paragangliomas are rare but clinically significant due to their malignant potential. Radical surgery with meticulous perioperative hemodynamic control is the cornerstone in recurrent/metastatic disease. Lifelong follow-up with imaging and biochemical surveillance is mandatory.