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.