A patient with a mucinous appendiceal cancer presents to the surgeon complaining of abdominal discomfort and nausea. Having undergone a prior right hemicolectomy, the patient has been disease free and on surveillance with clinical and carcinogenic antigen (CEA) monitoring. The CEA was noted to be elevated and a computed tomography scan revealed peritoneal nodules throughout the abdomen with a presumptive diagnosis of pseudomyxoma peritonei (progressive peritoneal implants from a mucinous primary). Several therapeutic options were offered and the patient selected to undergo cytoreductive surgery (CRS) with the potential to receive hyperthermic interoperative chemotherapy (HIPEC). Extensive resection was performed, including removal of the entire greater omentum, partial gastrectomy, and total pelvic exenteration with end colostomy and ileal conduit. Reassessment of the peritoneal cavity after the resections revealed almost complete cytoreduction. HIPEC was performed with mitomycin C and, after drainage and abdominal washing, the intestinal segments were anastomosed and the abdominal wall closed. Seven days postoperatively, an acute abdomen with septic shock developed as a result of a leak from the ileocolonic anastomosis. The patient returned to the operating room and an exploratory laparotomy, a small bowel resection, a resection of the ileocolonic anastomosis, and an abdominal washout were performed. Edema of the bowel caused by peritonitis resulting from the anastomotic leak necessitated delayed closure of the abdominal wall. A temporary abdominal closure using the ABThera™ Open Abdomen Negative Pressure Therapy system was applied and the abdomen was eventually closed.