Intra-abdominal mucinous adenocarcinoma of urachal origin: report of a case.

Intra-abdominal mucinous cystic tumors can be difficult to diagnose preoperatively. We report a case of histologically diagnosed primary urachal adenocarcinoma: a rare type of bladder tumor. This case report is interesting for clinicians. The patient was an 86-year-old man who presented with acute abdominal pain. Computed tomography (CT) showed a large cystic mass with calcification, near the apex of the urinary bladder. Laparotomy revealed a large intra-abdominal cystic mass adherent to the anterior abdominal wall and superior to the urinary bladder. We performed laparoscopic-assisted resection and partial cystectomy. The cystic mass measured approximately 15 × 14 × 11 cm and contained mucinous material. Histological examination revealed that it extended to the muscle of the bladder wall and that its epithelium was composed of atypical cells with increased papillary morphology. The mucinous material was glycoprotein with degenerative fatty tissue, and calcification was recognized partly in the specimen. Thus, we comprehensively diagnosed a mucinous cystic adenocarcinoma of urachal origin.