Laryngeal leiomyosarcoma: histological, immunohistochemical and ultrastructural study of one case with review of the literature. Leiomyosarcoma of the larynx have rarely been reported and a review of the literature has yielded only 8 cases. Authors report a case in a 45-year-old patient. Histological exam of the surgical specimen showed a malignant spindle cell tumor. Ultrastructurally, neoplastic cells presented some features of smooth-muscle cells. Immunohistochemical studies revealed that most tumor cells coexpressed vimentin and smooth-muscle actin.