[A Case of Asymptomatic Paraganglioma of the Bladder].

Bladder paraganglioma is an extremelyrare tumor, accounting for 0.7% of all paragangliomas and less than 0. 05% of all bladder tumors. While often discovered due to catecholamine-related symptoms or urinary symptoms, preoperative diagnosis in asymptomatic cases is difficult but crucial to avoid intraoperative hypertensive crises. Here, we report a case of asymptomatic paraganglioma of the bladder that was incidentallydiscovered. An 82-year-old woman was referred for evaluation of an incidental bladder tumor. Contrast-enhanced CT and cystoscopy revealed a submucosal tumor in the posterior bladder wall. MRI showed a high signal on T2-weighted imaging and earlyarterial enhancement on fat-suppressed T1-weighted imaging. Endocrinological studies revealed no obvious catecholamine excess, but ¹²³I-MIBG scintigraphy confirmed uptake in the bladder tumor, leading to a preoperative diagnosis of bladder paraganglioma. After preoperative management with an alpha-blocker (doxazosin), laparoscopic partial cystectomyand sigmoid colectomywere performed simultaneously. During tumor resection, the patient's systolic blood pressure rose to 220 mmHg temporarilybut was well controlled, and the surgerywas completed safely. Pathology confirmed bladder paraganglioma. The postoperative course was uneventful, and no recurrence has been observed 13 months after surgery. Even in asymptomatic bladder tumors, bladder paraganglioma should be considered. Appropriate imaging and endocrine evaluation are essential for a safe and effective treatment strategy.