Immunohistochemical expression of Galectin-3 and HBME-1 in granular cell tumors: a new finding.

Granular cell tumor (GCT) is a relatively rare neoplasm, usually located in the upper aerodigestive tract, skin and soft tissue. Because of its uncertain histogenesis, GCT has been the object of many immunohistochemical and ultrastructural studies that have suggested a Schwann cell origin. Our recent observation of a case of GCT immunoreactive for Galectin-3 and HBME-1 led us to further investigate the immunohistochemical profile of these neoplasms. We evaluated the immunohistochemical expression of the traditional markers for GCT (S-100, CD68) along with new markers (Galectin-3, HBME-1, Calretinina and Inhibin-alpha) in 22 granular cell tumors. Our results showed, in all cases, a constant diffuse positivity for S-100 protein, CD68 and Galectin-3. HBME-1 was positive in 95% of cases. The present study gives a new immunophenotypic profile for GCT, which could help pathologists in distinguishing morphologically ambiguous granular lesions in unusual sites.