Immunohistochemical study of granular cell tumour

Immunoperoxidase studies were performed on 8 granular cell tumours using various intermediate filament proteins, as well as lysozyme, S-100 protein, and lectins. All the lesions gave negative results to cytokeratin, vimentin, desmin, myoglobin, neurofilament protein, glial fibrillary acidic protein and lysozyme. One was positive for alpha-1-antitrypsin and alpha-1-antichymotrypsin. S-100 protein and lectins (Concanavalin ensiformis and Triticum vulgaris) were uniformly positive in all the lesions. S-100 protein positivity would indicate that granular cell tumours are of neural or neuroectodermal origin, although the cell type involved is not clear. There is no obvious explanation for the lectin-binding properties of granular tumour cells. It is hoped that further studies will evaluate the usefulness of lectin histochemistry in defining the nature of granular cell tumours.