Myoepithelioma of soft tissue

A myoepithelioma occurred in the subcutaneous tissue of the right shoulder of a 28-year-old man. The well-demarcated nodular tumor (3.0 x 2.8 cm) was located in the subcutaneous tissue with no adhesion to the deltoid muscle. The tumor was composed of a fascicular proliferation of spindle cells with variable amounts of stroma and showed areas of Sheets of epithelioid cells, In most areas, the tumor cells had uniform nuclei, but pleomorphic epithel ioid cells were focally present. Mitotic activity was three per 10 high-pow er fields. No ductular structure was found throughout the tumor. Immunohist ochemical and ultrastructural studies confirmed the myoepithelial origin of the tumor cells. The occurrence of myoepithelioma in the subcutaneous tiss ue has been rarely reported. Even though the tumor showed no aggressive beh avior on the 2-year followup, it is still too early to comment definitely o n the behavior of myoepithelioma of the subcutaneous tissue. This case prov ides further information about soft tissue myoepithelioma.