[A Case of Reoperation for Recurrent Carcinoma at a Colostomy Site Following Conversion from Laparoscopic to Open...

Colostomy site carcinoma is an extremely rare clinical entity, particularly as a form of postoperative recurrence. We report a case of recurrent adenocarcinoma at the colostomy site following surgery for rectosigmoid cancer. A male patient in his 70s initially underwent laparoscopic Hartmann's procedure, which was converted to open surgery due to tumor size. While receiving adjuvant CAPOX chemotherapy, a granuloma-like mass at the colostomy site gradually enlarged. Initially considered an inflammatory change, conservative treatment was given;however, due to continuous growth, biopsy was performed and confirmed adenocarcinoma. Given the risk of bowel obstruction from the tumor, resection of the colostomy site along with reconstruction of a new stoma was undertaken. Histopathological findings revealed well-differentiated adenocarcinoma. Postoperatively, the patient resumed systemic chemotherapy with bevacizumab plus FOLFIRI. This case highlights the clinical importance of considering malignant recurrence even when stoma-associated lesions initially resemble benign granulation. Early diagnosis and appropriate surgical intervention are essential for optimal outcomes. We present this case to emphasize the need for vigilant long-term stoma surveillance and rapid diagnostic action in the presence of suspicious lesions.