A resected case of medullary carcinoma of the ascending colon followed by infarction of the greater omentum mimicking anastomotic leakage

Introduction Medullary carcinoma is a rare type of colorectal adenocarcinoma, and omental infarction is a rare cause of acute abdomen. Presentation of case A 72-year-old woman underwent single-incision laparoscopic right hemicolectomy for ascending colon cancer. Pathological examination showed a medullary carcinoma (MC) of T4aN0M0 Stage IIB. Her postoperative course was uneventful, and she was discharged on postoperative day (POD) 6. From POD 7, she suffered from fever, and she returned to the hospital on POD 9. Plain computed tomography showed free air beside the anastomotic site around the elevated density of fat tissue and gallbladder wall thickening with a gallstone. Suspecting anastomotic leakage with acute cholecystitis, probe laparotomy was performed. Intraoperative observation confirmed omental infarction with acute cholecystitis, and no leakage was found at the anastomotic site. Therefore, the necrotic part of the greater omentum was resected, and cholecystectomy was performed. She has remained well, with no evidence of recurrent cancer during the 12 months of follow-up without chemotherapy after the surgery for MC of the ascending colon. Discussion MC should be distinguished from other more aggressive, non-glandular tumors of the colon because MC appears to have a better survival outcome than undifferentiated colon adenocarcinoma. Omental infarction should be considered in the differential diagnosis of acute abdomen after surgery. Conclusion A rare case of medullary carcinoma of the ascending colon followed by infarction of the greater omentum mimicking anastomotic leakage is presented.