Isolated colostomy site recurrence in rectal cancer-two cases with review of literature

BACKGROUND: Colostomy site carcinomas are rare with only eight cases reported in the world literature. Various etiological factors like adenoma-cancer sequence, bile acids, recurrent and persistent physical damage at the colostomy site by faecal matter due to associated stomal stenosis have been considered responsible. Two such cases are being reported and in both cases there was no evidence of any local recurrence in the pelvis or liver and distant metastasis. Both patients had received adjuvant chemotherapy following surgery. CASE PRESENTATION: First case was a 30-year-old male that had reported with large bowel obstruction due to an obstructing ulcero-proliferative growth (poorly differentiated adenocarcinoma) at the colostomy site after abdomino-perineal resection, performed for low rectal cancer six years previously. Wide local excision with microscopically free margins was performed with a satisfactory outcome. Four years later he presented with massive malignant ascites, cachexia and multiple liver metastasis and succumbed to his disease. Second case was a 47-year-old male that presented with acute large bowel obstruction due to an annular growth (well differentiated adenocarcinoma) in the upper rectum. He was managed by Hartmann's operation and the sigmoid colostomy was closed six months later. Five years following closure of colostomy, he presented with two parietal masses at the previous colostomy site scar, which, on fine needle aspiration cytology were found to be well-differentiated adenocarcinomas of colorectal type. Surgery in the form of wide local resection with free margins was performed. He presented again after five years with recurrence along the previous surgery scar and an incisional hernia and was managed by wide local excision along with hernioplasty. Follow-up of nine years following first surgery is satisfactory. CONCLUSION: Colostomy site/scar recurrence of rectal carcinoma is rare and could be due to various etiological factors, although the exact causative mechanism is not known. Surgery with microscopically free margins is recommended in the absence of metastatic disease. Stenosis of the stoma is considered as one of the most important contributory factors and should be followed carefully.