Rare case of perplexing ovarian endometriosis.

Objective: To document a rare case of coexisting endometriosis and mature cystic teratoma in the same ovary.

Design: Case report.

Setting: Gynecology unit in a tertiary training and teaching hospital in Cape Town, South Africa.

Patient(s): A 30-year-old healthy nulligravida woman with a large ovarian tumor.

Intervention(s): After a basic examination, a diagnostic and management laparotomy was performed. A unilateral oophorectomy and staging laparotomy were performed.

Main Outcome Measure(s): Final diagnosis of a complex ovarian tumor.

Result(s): Histologic analysis confirmed endometriosis of the pelvis and concomitant compound pathology in the right ovary, which included endometriosis, mature teratoma, and mucinous cystadenoma.

Conclusion(s): Co-existence of varied pathology in a single organ presents a challenge to the pathologist and the clinician. Accurate clinical (i.e., surgical) assessment and decisive histologic verification forms a critical part in this process. This case of coexisting endometriosis and teratoma in a single ovary is, to our knowledge, only the third case reported in literature.