Background: Adenomyoma is a benign tumour composed of smooth muscle and benign endometrium. These tumours typically originate within the uterus. An extra-uterine adenomyoma is a rare entity.
Case: We report a case of extra-uterine adenomyoma of the ovarian ligament, which was an incidental finding during a total abdominal hysterectomy and bilateral salpingo-oophorectomy for a benign ovarian tumour in a postmenopausal woman. The mass was round with uterine-type smooth muscle and scattered functional endometrial glands and stroma.
Discussion: Only seven other cases of an extra-uterine uterine-like mass are reported in the literature. There have been no cases of adenomyoma in the ovarian ligament reported until now.
Conclusion: It is most likely that this uterine-like mass arose from the tissues of the secondary müllerian system.