Metastatic colon cancer of an ovarian cancer origin mimicking primary colon cancer: A case report

ABSTRACT

Metastatic colorectal cancer is rare and its origins are difficult to define if the gross features of colorectal cancer mimic primary colorectal cancer. However, accurate diagnosis is essential because the treatment and prognosis may vary depending on the origin of the cancer. This report is about a 74-year-old female patient with metastatic sigmoid colon cancer of ovarian origin that mimicked primary sigmoid colon cancer. She spent a 3-year period disease-free from ovarian cancer after surgery and adjuvant chemotherapy. At the time of initial diagnosis, the cancer was diagnosed as a primary sigmoid colon cancer, because the cancer appeared to be a solitary intra-luminal fungating mass. However, the final pathologic result showed that the cancer was metastatic sigmoid colon cancer of ovarian origin and it was confirmed by immunohistochemical staining of cytokeratins-7, -20, and Wilms tumor-1. Therefore, even if colorectal cancer is a single intra-luminal lesion, patients should be suspected of having metastatic colorectal cancer if they have other cancer histories. At this time, immunohistochemical staining using various cancer markers may be a useful tool to distinguish the origin of cancer.