Leiomyosarcoma of the breast. Report of a case and review of the literature.

Leiomyosarcomas usually arise in the gastrointestinal tract, uterus, or soft tissues. Primary leiomyosarcoma of the breast is an exceedingly rare tumor of which only 14 cases have been reported in the literature. Leiomyosarcomas are thought to arise from preexisting smooth muscle cells. A number of hypotheses are suggested to explain how this tumor type develops in the breast, which contains few smooth muscle cells. With reference to a case of leiomyosarcoma of the breast and of data from the literature, the diagnostic, therapeutic, and prognostic criteria for these tumors are discussed.