Endometriosis mimicking an ovarian malignancy: A rare case report

Background: Endometriosis is a common gynecological condition that in sporadic cases can mimic an ovarian malignancy. We report a unique case of endometriosis characterized by massive hemorrhagic ascites and a mass-like plaque on the uterine surface. Atypical endometriosis is recognized as a potential precursor to ovarian malignancies. Case presentation: A 51-year-old woman with no significant medical history presented with abdominal pain, massive ascites and abnormal findings on ultrasound and CT. This, together with an elevated CA-125 level pre-operatively raised suspicion for ovarian malignancy. Diagnostic laparoscopy with frozen section biopsy was executed and the uterus and adnexa were removed. The final diagnosis however revealed an atypical presentation of endometriosis. Conclusion: This case highlights a rare manifestation of endometriosis that closely mimics ovarian malignancy. Clinicians should consider this differential diagnosis when encountering similar presentations.