Granular cell angiosarcoma of the skin: histology, electron microscopy and immunohistochemistry of a newly recognized tumor.

We report a unique angiosarcoma of the skin of the face in which a large part of the tumour was of granular cell appearance. Histologically the granular cells resembled those of conventional granular cell tumours. By electron microscopy the granules were identical to those of granular cell tumours but other features were lacking. Stains for vimentin and factor VIII related antigen were positive, but for S-100 protein and CEA were negative. The occurrence of granular cell change in an angiosarcoma supports the view that granular cell tumours are histogenetically diverse.