Smooth muscle is derived from primitive mesenchyme and is found mainly in the walls of blood vessels, erector pili musculature of the skin, circumvallate papilla, primitive mesenchyme and myoepithelial cells of salivary glands. Smooth muscle tumors in this region presumable originate from these sources. The benign counterpart of leiomyosarcoma is leiomyoma. Differentiation is based on the presence of mitotic figures. The world literature contains eighty cases of leiomyoma arising in head and neck structures, most commonly the tongue.
Primary treatment is local excision.
Leiomyosarcoma is the malignant smooth muscle tumor. Since 1950, only 38 cases of leiomyosarcoma of the head and neck structures have been reported. Twenty-seven patients were male, and eleven were female. Ages ranged from 2 months to 88 years, the average age being 45 years. Six cases occurred in children.