PARANASAL GIANT-CELL FIBROBLASTOMA - CASE-REPORT AND IMMUNOHISTOCHEMICAL FINDINGS

Few published reports describe patients with giant cell fibroblastoma, a rare, benign soft-tissue tumor that recurs locally and predominantl y arises in children. A 4-year-old boy underwent surgery for removal o f a giant cell fibroblastoma in the paranasal region, an unusual site. Six months after excision the tumor recurred locally. Immunohistochem ical examination of the primary tumor and recurrence revealed vimentin positive staining in the cytoplasm of all the cells. The multinucleat ed giant cells and the flat cells bordering the vessel-like spaces wer e negative for Factor VIII-related antigen, S-100 protein, actin and d esmin. Some histiocytes stained positively for alpha-1-antitrypsin, al pha-1-antichymotrypsin, antimacrophage and lysozyme antibodies. These immunoreactions indicate that giant cell fibroblastomas have a fibrohi stiocytic origin.