Bladder paraganglioma with renal agenesis: A possible new association and its implications in the light of REarranged in transfection gene genetics

Pheochromocytoma/paraganglioma and renal agenesis are commonly reported conditions. Their coexistence, however, is rare, with few cases reported. We report the case of a 21-year-old male who presented with painless hematuria. He was found to have congenital absent right kidney along with bladder mass on imaging. Examination including blood pressure was normal. He underwent cystoscopy that showed a solid looking tumor on the anterior wall. Paraganglioma was suspected due to intraoperative rise in blood pressure during resection and was confirmed on histopathology. Subsequently after work up and preoperative alpha blockade, patient underwent partial cystectomy and excision of the paravesical mass. Histopathology showed paraganglioma confined to bladder wall with surgical margins free and a paravesical mass that was seminal vesicle cyst. On follow-up, patient is normotensive and asymptomatic. This coexistence of paraganglioma and renal agenesis may have a common genetic mechanism in the form of REarranged in Transfection (RET) gene mutation. This is a well-characterized gene, mutations of which are known to be associated with both conditions. Current knowledge of the role of RET gene in both conditions is reviewed to put forth RET mutation as the possible common underlying genetic mechanism along with possible clinical implications of the combination.