Chemotherapy Toxicity Confirms Diagnosis of Urachal Carcinoma

The urachus is a fibrotic remnant of the allantois, a canal that collects liquid waste and exchanges gases from the fetal bladder with the umbilical cord. Urachal cancer is a rare and aggressive cancer that often presents as adenocarcinoma at the dome of the bladder.If urachal carcinoma is found early and confined to the urachus, cystectomy with en bloc resection of the urachal ligament and umbilicus can be curative. For unoperable patients, chemotherapy has a low rate of efficacy.In this case we explore the effects of Gem-FLiP (gemcitabine, 5-fluorouracil, leucovorin, and cisplatin) in the treatment of urachal carcinoma, a regimen that is undergoing clinical trials. A 76-year-old man with a long history of genitourinary disease presented with gross painless hematuria. A flexible cystoscopy showed a sessile tumor at the dome of the bladder. A computed tomography (CT) urogram of the abdomen and pelvis confirmed a mass at the dome of the bladder. A CT-guided biopsy revealed adenocarcinoma consistent with urachal cancer.After beginning treatment with Gem-FLiP, he developed pedal edema as well as drainage of the umbilicus. A CT scan of the abdomen and pelvis showed an anterior extension through the abdominal wall just below the umbilicus with central hypoattenuation within the mass; this represented a fistula between the bladder and umbilicus, along the tract of the urachal ligament, therefore confirming the diagnosis of urachal cancer.This case illustrates a clinical scenario in which urachal carcinoma was confirmed when the entire cancerous urachus fistulized in response to treatment with systemic chemotherapy. It is highly unusual that a response to chemotherapy confirms a diagnosis.