A Rare Case of Transitional Cell Carcinoma in an Adult Male With Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder characterized by café-au-lait macules on the skin, Lisch nodules of the iris, and predisposition to a wide array of tumors. These include neurofibromas, pheochromocytomas, and gastrointestinal stromal tumors (GIST). While there is documented evidence to suggest that the NF1 gene may play a role in the pathogenesis of transitional cell carcinoma (TCC) of the bladder, there is a paucity of documented cases of TCC in patients with NF1. Our patient is a 53-year-old male with a known diagnosis of NF1 and prior history of GIST who presented to the emergency department with lower abdominal pain, constipation, hematuria, and oliguria. The patient was found to have marked colonic distention prompting a decompressive cecostomy with subsequent return of bowel function. Cystoscopy was performed at this time for hematuria, which revealed a 9 cm bladder mass. Pathology showed a high-grade TCC of the bladder with nuclear pleomorphism and necrosis. The patient was treated with gemcitabine and cisplatin neoadjuvant chemotherapy, followed by cystoprostatectomy with bilateral pelvic lymphadenectomy and ileal conduit urinary diversion. Our case report is the first documented instance in the United States exhibiting an in vivo association of NF1 with the development of TCC of the bladder, an association previously identified in vitro. We hope our work inspires further investigation into this unique association.