A Rare Case of Intramural Müllerian Adenosarcoma Arising from Adenomyosis of the Uterus

Müllerian adenosarcomas usually arise as polypoid masses in the endometrium of post-menopausal women. Occasionally, these tumors arise in the cervix, vagina, broad and round ligaments, ovaries and rarely in extragenital sites; these cases are generally associated with endometriosis. We experienced a rare case of extraendometrial, intramural adenosarcoma arising in a patient with adenomyosis. A 40-year-old woman presented with sudden-onset suprapubic pain. The imaging findings suggested leiomyoma with cystic degeneration in the uterine fundus. An ill-defined ovoid tumor with hemorrhagic degeneration, measuring 7.5 cm in diameter, was detected. The microscopic findings showed glandular cells without atypia and a sarcomatous component with pleomorphism and high mitotic rates. There was no evidence of endometrial origin. To recognize that adenosarcoma can, although rarely, arise from adenomyosis is important to avoid overstaging and inappropriate treatment.