Identical twins with ovarian endometriosis and mucinous borderline tumor: an unusual association.

Objective: To report a case of monozygotic twins with unilateral ovarian tumors of different histology and character.

Design: Case report.

Setting: Medical center and teaching hospital.

Patient(s): A 22-year-old woman with ruptured ovarian endometrioma and her twin with mucinous borderline tumor of the ovary.

Intervention(s): Ultrasonography, laparoscopic ovarian cystectomy, and salpingo-oophorectomy.

Main Outcome Measure(s): Ovarian cystectomy for the twin with endometrioma and examination of the asymptomatic twin.

Result(s): Diagnosis and treatment of the asymptomatic twin.

Conclusion(s): Ovarian tumors present in monozygotic twins may not always be of the same histologic type.