Malignant caeco-sigmoid fistula.

To cite: ElGendy K, Salem A. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014207106 DESCRIPTION A 60-year-old woman presented with a 2-month history of bleeding per rectum and recent change in bowel habits in the form of diarrhoea. The patient has no comorbidities and no family history of colon cancer. Abdominal examination was insignificant aside from a mass in the right lower quadrant, which was soft, non-tender and ill-defined. Routine laboratory investigations were within normal limits. Colonoscopy was performed and revealed two synchronous lesions in the colon (figure 1), ileocaecal mass (A) and sigmoid mass (B). Both biopsies showed moderately differentiated adenocarcinoma. CT (chest, abdomen, pelvis) revealed a mass in the right iliac fossa involving the sigmoid, ileum, caecum and appendix with fistula communicating the sigmoid with the caecum (figure 2), with no evidence of liver, lung or distant metastasis. Surgery was offered to the patient in the form of right hemicolectomy and anterior resection with primary anastomosis. The patient had a smooth postoperative course. Pathological examination showed the primary tumour in the caecum involving the sigmoid through a communicating fistula (figure 3), with no involvement of lymph nodes. The tumour was confirmed to be low-grade adenocarcinoma with a mucinous component. In addition, there was involvement of the circumferential resection margin of the proximal caecum. However, other risk factors (eg, perineural invasion, lymphovascular invasion) were negative. The final staging according to AJCC was T4b, N0, M0, which is the stage IIC/Duke B. Owing to the