A Case of Early Colorectal Cancer with Invasive Micropapillary Carcinoma Component with Peritoneal Dissemination Recurrence

A 64-year-old woman visited a nearby hospital complaining of bloody stool. Total colonoscopy revealed an Ip tumor in the sigmoid colon, so she was referred to our hospital and endoscopic resection was performed. The histopathological find-ings confirmed a well-differentiated adenocarcinoma that had invaded the submucosal layer, and part of the tumor con-tained invasive micropapillary carcinoma （ IMPC ） and positive lymphatic invasion was seen. She underwent single-port laparoscopic sigmoid colectomy with D3 lymph node dissection. Regional lymph node metastasis was positive, which was pStage Ⅲ a. During postoperative adjuvant chemotherapy, tumor markers were elevated, and CT revealed recurrence of peritoneal dissemination. Multidisciplinary treatment including chemotherapy was performed. We experienced 16 cases of colorectal cancer containing IMPC in the seven-year period from 2013 to 2020. Colorectal cancer containing IMPC has a high incidence of lymphatic metastasis ； it is considered necessary to examine the degree of lymph node dissection with due consideration of the possibility of lymph node metastasis.