Benign metastasizing leiomyoma of the uterus.

Herein, we report on a well-characterized benign metastasizing leiomyoma, presented in an unusual site. Up to the knowledge of authors, so far, only 76 cases of benign metastasizing leiomyoma have been reported. The tumor presented as a retroperitoneal mass three years after a hysterectomy Performed for leiomyomatosis of the uterus with extensive areas of hyalinization. Histopathologic and immunohistochemical studies of the resected mass were similar to the uterine leiomyoma, showing moderate cellularity of bland looking smooth muscle cells with minimal atypia, inconspicuous mitosis, and no necrosis in a hyalinized background.