- Leiomyosarcoma is a malignant tumor that can arise from smooth muscle or from pluripotential, undifferentiated mesenchymal cells. In the head and neck, smooth muscle is sparse and found mainly in the walls of blood vessels and the erector pili muscles of the skin. The occurrence of leiomyosarcoma in the head and neck region is rare. The purpose of this report is to describe a case of leiomyosarcoma of the pinna. To our knowledge, the present case is only the second case of leiomyosarcoma of the pinna reported.