Metastatic Ovarian Mucinous Carcinoma Presenting as Ileocecal Adenocarcinoma: A Case Report.

Colorectal invasion is an unusual late-stage presentation of metastatic primary mucinous ovarian cancer. In this article, we report a fatal case of a 65-year-old female who presented to our clinic with progressive weight loss, severe constipation, and postprandial early satiety. She underwent an esophagogastroduodenoscopy (EGD) and colonoscopy. Direct visualization during colonoscopy revealed acute inflammation with ulceration and highly atypical glands in the ileocecal valve. The initial biopsy was unremarkable, and a repeat biopsy was performed due to high suspicion of malignancy. The repeat biopsy revealed poorly differentiated, invasive colon adenocarcinoma with partial mucinous features. The patient was referred to the surgery service. While planning for surgical resection, they obtained a CT abdomen and pelvis, which revealed a large ovarian mass and peritoneal carcinomatosis. Immunohistochemistry for the tumor cells was positive for pancytokeratin and cytokeratin 7, partially positive (up to 20%) for cytokeratin 20 and CDX2, and negative for estrogen receptors, monoclonal carcinoembryonic antigen (CEA), and synaptophysin. This immunophenotypic pattern is strongly consistent with metastatic mucinous carcinoma of ovarian origin.