免疫染色によって術前診断しえた卵巣癌同時性大腸転移の 1 例

While undergoing colonoscopy for hematochezia, a 47-year-old female was found to have an ulcerous lesion associated with a submucosal tumor (SMT), in the sigmoid colon. It was diagnosed as a poorly differentiated adenocarcinoma by H&E staining. CT and MRI showed intrapelvic tumors, in addition to the sigmoid colon tumor. The tumor marker CA 125 was high. The sigmoid colon tumor was CK7(+), CK20(-), and Pax-8(+) by immunostaining and it was diagnosed as a metastatic tumor of gynecologic carcinoma. Diagnostic laparoscopy revealed disseminated nodules in the mesentery and pelvic floor, but there were no abnormalities in the ovaries, and the patient was diagnosed with primary peritoneal carcinoma. Debulking surgery was successfully performed after 3 courses neoadjuvant chemotherapy of carboplatin and paclitaxel. The final diagnosis was ovarian carcinoma because a similar histological pattern was also observed in the ovarian parenchyma. There are few reports of synchronous colorectal metastasis from ovarian carcinoma. Immunostaining is important for differential diagnosis of malignant colorectal tumors with intrapelvic tumors.