SAT-376 Case Report of a Clinically Silent Paraganglioma of the Urinary Bladder

Abstract M. Herrera: None. M. Ahmad: None. S. Shah: None. P. Ucciferro: None. Introduction: Pheochromocytomas (PCCs) and paragangliomas (PGLs), both grouped together as PPGLs, are tumors derived from cells of neural crest origin located in the adrenal medulla or extra adrenal autonomic paraganglia, respectively. PGLs account for approximately 15% of all PPGLs and represent 0.06% of bladder tumors. Typical clinical manifestations include episodic headaches, palpitations, paroxysmal hypertension, and sweating. We describe an interesting case of an incidental PGL of the bladder. Case presentation: The patient was an 80-year-old female with a past medical history of type 2 diabetes mellitus, hypothyroidism, CKD, and hypertension who had a routine renal ultrasound that showed a bladder mass. Cystoscopy confirmed a 2.5 cm submucosal mass arising from the left bladder wall adjacent to the left ureteral orifice. CT abdomen/pelvis evidenced a mass lesion of 17 x 16.3 mm in the posterior left side of the urinary bladder without evidence of adenopathy or metastatic disease. Patient underwent transurethral resection of bladder tumor and remained hemodynamically stable during the procedure. Histopathologic findings were consistent with bladder PGL. Tumor cells were positive for chromogranin, synaptophysin and GATA3. S100 highlighted sustentacular cells. At that point, patient denied any personal or family history of PCCs, PGLs, VHL, MEN, or other endocrine tumor syndromes, as well as classic spells. Serum markers showed chromogranin A of 2235 ng/mL, free metanephrines of 49 pg/mL, and normetanephrines of 442 pg/mL. Repeat serum markers levels three weeks after resection showed chromogranin A of 1330.0 ng/mL, free metanephrine of 30.2 pg/mL, and normetanephrines of 217.1 pg/mL, as well as 24hr urine metanephrines of 141 ug/24hr, and normetanephrines of 810 ug/24hr. Following two weeks, repeat Chromogranin A was 1590 ng/mL. Blood pressure remained controlled with beta and alfa blockage and patient will continue with disease surveillance in the future. Conclusion: PGLs are rare tumors with diverse presentations that go from headaches, palpitations, and sweating to clinically silent. Determinants of the silent phenotype are small tumor size, amount, and types of catecholamines produced, constant or intermittent nature of secretion, and compensatory responses to prolonged catecholamine stimulation. Postoperative surveillance is crucial for early detection of incomplete resection, recurrence, or metastasis, especially considering the significantly higher proportion of PGLs (35% - 40%) that develop metastases in comparison with PCCs (10 -15%). We described a silent PGL with down trending, but persistently elevated chromogranin A levels postresection. Raising awareness about this uncommon diagnosis, its silent presentation and importance of postoperative surveillance, can guide clinical decisions that improve medical outcomes. Saturday, June 1, 2024