Primary leiomyosarcoma of the breast: report of a case.

We describe herein a case of primary leiomyosarcoma of the breast in a 59-year-old woman. Preoperative clinical examination and cytology findings indicated a benign breast tumor, but intraoperative histopathological examination of the tumor revealed malignant spindle cells, and a modified radical mastectomy was performed. Immunohistochemical analysis subsequently confirmed a diagnosis of leiomyosarcoma. Primary leiomyosarcoma of the breast is extremely rare and difficult to diagnose before surgery because of the need for mitotic figures and immunohistochemical staining to confirm the diagnosis. When pre- and intraoperative examinations indicate the possibility of a leiomyosarcoma, an extended excision with sufficient margins should be performed to remove all of the affected tissue. A review of the literature on this unusual tumor of the breast is presented.