Uterine malignant leiomyoblastoma (epithelioid leiomyosarcoma) during pregnancy

A case of uterine malignant leiomyoblastoma (UML) which was initially mistaken for uterine leiomyoma on two different occasions is presented. About 20 cases of uterine leiomyoblastoma taking a malignant course have been described in the literature. This case of UML is the first diagnosed during pregnancy. In retrospect, tumor tissue removed from the uterus 4 years earlier already showed histological signs of UML. The large and metastatic tumor showed nuclear atypia, a moderate mitotic index, and tumor cell necrosis, indicating malignancy. Treatment consisted of hysterectomy, bilateral salpingo-oophorectomy, and debulking of most other tumor masses. In the literature, radio- and chemotherapy have not proved to be effective in these tumors. Hormonal therapy has only been used in 2 patients. In this patient, hormonal influence on tumor growth may be substantial. The tumor was progesterone- and estrogen-receptor positive and increased in size rapidly during pregnancy. Since little is known about these tumors further studies are necessary to evaluate hormonal influences both as a causative factor and as a therapeutic possibility.