Diagnostic challenges in synchronous ovarian metastasis from rectal cancer: A case report.

Introduction: Ovarian metastases from rectal cancer are infrequent; thus it might be hard to diagnose and treat them. Our study introduces a challenging case which highlights our method in addressing such an issue.

Patients Concerns: A 74-year-old woman was admitted to our Unit showing abdominal pain, vomit, and a gross abdominal mass located in the right iliac fossa and mesogastrium. Oncological markers recorded following abnormalities: carbohydrate antigen 19.9 (Ca19.9) = 453.40 U/mL, carbohydrate antigen 125 (Ca125) = 88.3 U/mL.

Diagnosis: Such a metastatic tumor being difficult to diagnose, we could not achieve a precise preoperative diagnosis. We entered the operating room with a histologic diagnosis that was highly suspicious of colon adenocarcinoma. During surgery, frozen section analysis was positive for primary ovarian cancer. Thanks to the immunohistochemistry test on the histologic specimen, which might be very helpful in diagnosing such metastatic tumor, final pathology report documented ovarian metastasis from rectal cancer.

Interventions: We performed total hysterectomy with bilateral salpingo-oophorectomy and low anterior resection of the rectum with a terminal colostomy. Adjuvant chemotherapy was administered for 6 months using FOLFOX plus panitumumab in first-line therapy.

Outcome: At 8 months from surgery, during follow-up, a local pelvic progression of disease was detected, leading to second-line chemotherapy treatment.

Conclusion: Correct differential diagnosis between primary and metastatic ovarian tumors is paramount in choosing the best treatment which leads to the best possible outcome. In ovarian metastatic tumors, immunohistochemistry could represent an optimal diagnostic tool.