A case of Krukenberg carcinoma metastasized from colon cancer resembling mucinous cystadenocarcinoma of the ovary

We report a case of a 44-year-old woman with bilateral ovarian carcinoma that had metastasized from the colon and mimicked primary mucinous cystadenocarcinoma. Macroscopically, both ovarian tumors were large, multiloculated cystic masses with abundant mucinous content. Histologically, they were lined with mucinous epithelium with mild to moderate nuclear atypia and showed stromal invasion and surface involvement. At first, the tumors were diagnosed as bilateral primary ovarian mucinous cystadenocarcinomas. However, three months after surgery, a large villous tumor was discovered in the ascending colon by colonoscopic examination and was surgically resected. Histologically, the colonic tumor was a villous adenomatous tumor with invasive components of mucinous adenocarcinoma composed of well-differentiated adenocarcinoma and exhibited abundant extracellular mucin production. As a villous adenomatous component was present in the mucosal area, the colonic tumor was considered a primary tumor. Therefore, the original diagnosis of bilateral ovarian tumors was revised for consistent with metastasis from the colon carcinoma, in line with the findings of immunohistochemistry and loss of heterozygosity analysis. This case highlights the importance of considering the possibility of metastatic tumors from the gastrointestinal tract in the diagnosis of mucinous ovarian tumors.