The Ovarian Portal: An Unusual Pathway to Discovery, A Rare Initial Manifestation of Colon Cancer

Background/Aim: Ovarian metastases from colorectal carcinoma (CRC) are rare but have significant clinical implications, often resembling primary ovarian tumors. An incorrect diagnosis can result in delayed systemic therapy and surgical planning.

Case Report: A 56-year-old postmenopausal woman presented with right lower quadrant pain and postmenopausal bleeding. Pelvic ultrasound and computed tomography (CT) scans demonstrated a large, complex adnexal mass with thickening of the ascending colonic wall. She underwent diagnostic laparoscopy and subsequent total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy, tumor debulking, and right hemicolectomy. The postoperative pathology revealed a moderately differentiated adenocarcinoma of the cecum, with bilaterally metastatic involvement of the ovaries, omentum, peritoneal surfaces, and liver serosa. Immunohistochemistry confirmed the colonic origin (CDX2⁺, CK20⁺, CK7⁻). She was diagnosed with stage IVc (pT4aN2aM1c) colon adenocarcinoma and subsequently started on systemic treatment with mFOLFIRINOX with bevacizumab.

Conclusion: This case highlights the diagnostic challenge of distinguishing between primary ovarian carcinoma and metastatic colorectal adenocarcinoma, underscoring the need for multidisciplinary collaboration and immunohistochemical confirmation to inform treatment decisions.