Small Bowel Obstruction Due to Metastatic Urachal Adenocarcinoma: A Rare Presentation

Urachal adenocarcinoma is a rare but highly malignant epithelial cancer that accounts for <1% of all bladder malignancies and commonly presents with hematuria. We report a case of metastatic urachal adenocarcinoma presenting as bowel obstruction. A 54-year-old male patient with a history of alcohol abuse presented to the emergency with acute-onset, diffuse, cramping abdominal pain, worst in the epigastrium and lasting one day. Abdominal examination revealed moderate guarding and generalized tenderness with hypoactive bowel sounds. Imaging confirmed an evolving small bowel obstruction and a urachal remnant with a superimposed mass lesion. The patient underwent an exploratory laparotomy and a high-grade small bowel obstruction due to the mass was identified. An intraoperative frozen section identified adenocarcinoma. A biopsy of the urachal mass confirmed urachal adenocarcinoma. The final diagnosis was moderately differentiated urachal adenocarcinoma. The tumor was deemed unresectable due to the involvement of multiple loops of the small bowel and the mesentery of the small and large bowels. Systemic chemotherapy with 5-fluorouracil (5-FU), leucovorin, and oxaliplatin (modified FOLFOX-6) was initiated. Our patient did not report any prior urinary symptoms or recurrent abdominal pain, which are the common symptoms that urachal adenocarcinoma presents with. Bowel obstruction is a rare presentation of urachal adenocarcinoma since the spread of the disease to the viscera occurs much later in the course. This case report highlights a rare presentation of an even rarer malignancy.