Malignant Mixed Mullerian Tumor Arising from Adenomyosis of Uterus

ABSTRACT

Malignant mixed mullerian tumor (MMMT) is an unusual tumor composed of malignant epithelial and nonepithelial components in the same lesion and is subdivided into homologous and heterologous types. Epidemiologically, these tumors are associated with prior pelvic irradiation, functioning ovarian lesions, exogenous estrogen therapy and rarely endometriosis. We experienced a case of uterine MMMT which arose from adenomyosis in a 47-year-old woman who had no specific past medical history. The posterior uterine corpus showed a 3.5x3.0x2.0 cm sized, relatively well defined tumor mass within the background of the adenomyosis. The tumor was composed of well differentiated endometrial adenocarcinoma and sarcomatous stroma with foci of rhabdomyosarcomatous differentiation confirmed by immunohistochemical and electron microscopic studies. Through the immunohistochemical study, both the epithelial and nonepithelial components were positive for cytokeratin and it suggested that the sarcomatous area originated from metaplasia of the adenocarcinoma component. From the overall findings, it is regarded as an uterine heterologous MMMT which arose from adenomyosis.