Negative Urinary Fractionated Metanephrines and Elevated Urinary Vanillylmandelic Acid in a Patient with a Sympathetic Paravesical Paraganglioma

Abstract

Introduction: Paragangliomas have hereditary and sporadic presentations. Aim(s): There are few reports in the literature of paravesical paraganglioma. Materials and Methods: Case report Results: We report the case of a 50-year-old male with a 2.5 cm paravesical mass documented on abdominal CT. Biopsy was performed by urology and the patient developed hypertensive crisis during the biopsy. He denied family or personal history of hypertension, flushing, palpitations or syncope during miction. Immunohistochemistry documented intense and diffuse positivity for chromogranin and synaptophysin, focal reactivity for S100 protein and 1% Ki-67 index. With a conclusive histology of paraganglioma, we conducted several biochemical tests, obtaining normal results for urinary metanephrines: total metanephrines: 614 ug/24hrs (RV <900 ug/24 hrs), normetanephrine: 423 ug/24 hrs (RV <600 ug/24 hrs), metanephrine: 141 ug/24 hrs (RV <300 ug/24 hrs), chromogranin A and ionic calcium, but elevated urinary vanillylmandelic acid (28.2 mg/24hrs RV: <13.6 mg/24 hrs). A 18 Fluorodeoxyglucose positron emission tomography showed a single paravesical lesion. Presurgical treatment was started with prazosin, followed by metoprolol and amlodipine. Surgical resection was performed successfully and antihypertensive medication was discontinued. The patient remains asymptomatic and normotensive (unmedicated). Results of genetic testing are pending. Conclusion: Negative urinary fractionated metanephrines don't exclude paraganglioma.