An aggressive malignant smooth muscle neoplasm, arising from the larynx. It is characterized by a proliferation of neoplastic spindle cells. The disease is Monarch Disease Ontology identifier MONDO_0003374 (laryngeal leiomyosarcoma). Also known as: larynx leiomyosarcoma, leiomyosarcoma of larynx, leiomyosarcoma of the larynx.