Malignant myoepithelioma of the salivary gland--an untypical clinical course.

A case of malignant tumor developing from myoepithelial cells (malignant myoepithelioma) is presented. The primary focus was located in the region of the left submandibular salivary gland. A relapse and metastases were disclosed in the same salivary gland, in the lung and the left breast. Immunohistochemical studies demonstrated positive reactions for S-100 protein, cytokeratins, smooth muscle actin, vimentin, GFAP protein, p53 protein and Ki-67 antigen, and allowed for establishing the final histopathological diagnosis of malignant myoepithelioma.