Leiomyosarcoma with dedifferentiation in a premenopausal patient discovered after uterine artery embolization.

Although a hysterectomy is the most common treatment for relieving the symptoms attributable to uterine leiomyomas, uterine artery embolization (UAE) is now being used more frequently as an alternative to a hysterectomy. However, it is difficult to differentiate a leiomyoma from a leiomyosarcoma without performing a pathological examination. Reported herein is a rare case of leiomyosarcoma that showed dedifferentiation of the tumor cells after UAE. A premenopausal 48-year-old woman had been suffering from hypermenorrhea for 4 years before visiting the clinic. She underwent UAE for suspected symptomatic leiomyoma. Two months later, dilatation and curettage was performed because of genital bleeding and a necrotic mass was submitted for pathological examination. Three months after curettage, with renewed symptoms, endometrial biopsy was done, which confirmed pleomorphic sarcoma. Metastatic nodes to the lung were also found at that time. Multiple leiomyosarcomas and a leiomyosarcoma showing dedifferentiation of the uterine body were found on pathological examination. The patient had metastatic nodes to the brain later and died of metastatic disease 20 months in total after UAE. This is a rare case of leiomyosarcoma with dedifferentiation and multiple metastases occurring after UAE, suggesting that dedifferentiation could be derived from ordinary leiomyosarcoma and that the traumatic effect of curettage might cause early metastasis. The present case is a warning that careful and detailed evaluation of the uterine tumor are needed before UEA.