Abstract
A 48-year-old woman was found to have a type 2 lesion at the sigmoid colon by colonoscopy which was diagnosed as well differentiated adenocarcinoma by a biopsy. Abdominal CT scan revealed multiple liver metastases and regional lymph node swelling. Sigmoid colon cancer, cMP, cN1, cH3, cPx in cStage IV was diagnosed and surgery was performed. During surgery, the tumor which appeared to be regional lymph node swelling was clarified to be located in the sigmoid mesocolon and to have adhered to the small intestine. Accordingly sigmoidectomy and associated resection of the small intestine were performed. The postoperative course was uneventful and the patient was discharged from our hospital. After she was transferred to another hospital, CDDP + CPT-11 regimen was started. The histologic type of the sigmoid colon cancer was well differentiated adenocarcinoma with the depth of the tumor invasion of SM>5,000μm. The coexistence of poorly differentiated adenocarcinoma and endocrine cell carcinoma was identified from the mesocolon tumor and omental nodes. Although a possibility of differentiation from sigmoid colon cancer to endocrine cell cancer after lymph node metastasis could not completely be ruled out, considering the depth of the tumor invasion, it is inferred that multiple liver metastases and peritoneal dissemination of associated cancer of unknown primary might occur.
