Synchronous ovarian metastasis from colorectal cancer: A report of two cases.

Ovarian metastasis of colorectal cancer is relatively rare. The present study reports two cases of synchronous ovarian metastasis from colorectal cancer, which were managed by cytoreductive surgery. In case one, a 60-year-old female patient presented with a multilocular pelvic tumor and ascites. Virtual colonoscopy revealed a mass in the sigmoid colon; however, no tumor cells were identified on histological examination. Ovarian metastasis from sigmoid colon cancer was suspected and adnexectomy was subsequently performed. Histological examination of the excised tumor revealed adenocarcinoma. Immunohistochemical analysis of the resected tumor revealed positive staining for cytokeratin (CK)20 and caudal-type homeobox 2 (CDX2), and negative staining for CK7, estrogen receptor, progesterone receptor and inhibin. The immunohistological results supported the diagnosis of ovarian metastasis from sigmoid colon cancer. In case two, a 56-year-old female patient presented with a multilocular pelvic tumor and ascites. Colonoscopy identified a rectal tumor, and histological examination revealed moderately-differentiated adenocarcinoma, which was confirmed by cytological analysis of ascites. Subsequently, ovarian metastasis from rectal cancer with peritoneal dissemination was diagnosed, and left ovariectomy and transverse colostomy were performed. Histological examination of the excised tumor revealed moderately-differentiated adenocarcinoma, and immunohistochemical investigation revealed positive staining for CK20 and CDX2, but negative staining for CK7. These immunohistological results indicated ovarian metastasis from rectal cancer. Both patients recovered well and are currently undergoing regular follow-up examinations. The observations from the two cases indicate that ovarian metastases of primary colorectal cancer may present as pelvic tumors and, thus, preoperative examination of the gastrointestinal tract is required. Furthermore, even in cases of widespread colorectal cancer metastases, excision of the ovarian tumor is required to establish a histological diagnosis for the selection of appropriate treatments.