GIANT CELL TUMOUR OF TENDON SHEATH| An Immunohistochemical Study of 28 Cases

An immunohistochemical study was carried out on 28 cases of giant cell tumor of tendon sheath. Although this tumor has been considered to be of histiocytic origin on the basis of light and electron microscopic findings, there remains some debate about the histogenesis of the tumor. To clarify this point, by using the PAP method, each surgical specimen was stained for alpha 1-antitrypsin, alpha 1-antichymotrypsin, lysozyme, ferritin, neuron specific enolase, and S-100 protein. Tumor cells in fifteen out of 28 cases were positively stained for alpha 1-antitrypsin, 19 for alpha 1-antichymotrypsin, 23 for lysozyme, 22 for ferritin, 22 for neuron specific enolase, but no case for S-100 protein. These results suggest that this tumor is composed of cells with histiocytic character. In addition, from the immunohistochemical point of view, at least two types of giant cells seem to exist in this disease.