We report on a 48-year old female patient presenting with a spherical firm tumour that developed within a period of about three weeks. No causative trauma could be assessed. The tumour was surgically removed and turned out to be a leiomyosarcoma of the tongue. Probably the tumour originated from the vascular smooth muscle cells. Clinically this very rare tumour of the tongue must be differentiated from various benign and malignant mesenchymal neoplasms. Therapeutic considerations and differential diagnosis are discussed in reviewing the literature.