RF19 | PSUN367 Urinary bladder Paragangliomas – A Case series

INTRODUCTION: Paragangliomas (PGL) are rare neuroendocrine tumours and account for approximately 10% of all chromaffin tumours. They may occur in the retroperitoneum, mediastinum, skull and the urinary bladder. Paragangliomas of the urinary bladder are rare entities accounting for 10% of all paragangliomas and 0.06% of all bladder tumours. Approximately 10% of urinary bladder paragangliomas are malignant. Bladder paragangliomas can be either functional or non-functional. Main symptoms of functional PGLs are due to catecholamine excess with palpitations, paroxysmal hypertension during micturition, sweating and headaches. Functional bladder PGL are diagnosed on biochemical analysis. Non-functional bladder PGLs present with haematuria and are often misdiagnosed as bladder cancer as they may cystoscopically and histologically resemble a urothelial neoplasm. Clinical cases: We present a case series of 4 surgically treated patients with urinary bladder paragangliomas who presented to Cambridge University Hospital over the last 3 years. All patients were female with an age range between 21 and 44 years. All four patients had SDHB deficient tumours, and all four patients were diagnosed with a pathogenic variant in the SDHB gene. Three patients had no family history of SDHx associated neoplasia whereas one had a paternal aunt who died from a metastatic pheochromocytoma. Three patients had presented with palpitations and hypertensive episodes, one of whom experienced symptoms while micturating. Biochemical analysis revealed elevated plasma normetadrenaline levels in all patients. On presentations, one patient had a synchronous paratracheal paraganglioma while two patients had lymph node metastasis. All patients were surgically treated with two patients undergoing fertility preserving cystectomy and bladder substitution, one undergoing partial cystectomy, radical hysterectomy and ureteric implantation and one managed with robot-assisted partial cystectomy. None of the patients have evidence of biochemical or radiological tumour recurrence on follow-up with a mean follow-up time of 23 months (range 12 to 40 months). CONCLUSION AND POINTS FOR DISCUSSION: The diagnosis of urinary bladder PGL is challenging. Biochemical assessment to assess catecholamine production and imaging studies like CT, MRI and NM Ga68 DOTATATE PET CT are helpful modalities in diagnosis. Patients presenting with extra adrenal paragangliomas including bladder paragangliomas require genetic testing because of the strong hereditary predisposition, with mutations in the SDHx genes being most common with this clinical phenotype. The surgical approach should be tailored to the individual patient, agreed by a multi-disciplinary team and the risk of malignancy should be weighed against the potential morbidity associated with a curative oncological surgery. As urinary bladder PGLs have malignant potential and are frequently hereditary (as demonstrated in this series), lifelong follow-up is required to screen for synchronous tumours and tumour recurrence. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Sunday, June 12, 2022 12:42 p.m. - 12:47 p.m.