[Benign and malignant granular cell tumors. An immunohistochemical classification of tumor cells].

Eight benign and three malignant granular cell tumors were characterized by means of antibodies and antisera against keratin, desmin, epithelial membrane antigen, factor VIII-related protein, lysozyme, myelin basic protein, myoglobin, neurone-specific enolase, S 100 protein, myelin-associated protein (Leu 7), glial fibrillary acidic protein, vimentin, and neurofilament. All benign granular cell tumours showed positive staining of the tumor cells to antibodies against vimentin, S 100 protein, and neurone-specific enolase; myelin-associated protein (Leu 7), in contrast, was only detectable in a few tumor sections. Histogenetically the granular cells may be classified as Schwann's cells which lost their expression of laminin. The three malignant granular cell tumors showed a staining pattern significantly different from that of the benign tumours. Thus, only neurone-specific enolase was detectable in all the tumors, whereas S 100 protein and vimentin could not be demonstrated but in one and two, resp., out of three tumors.