UNUSUAL ULTRASTRUCTURAL FINDINGS IN GIANT-CELL FIBROBLASTOMA

We report on a 4-year-old boy with recurrent giant-cell fibroblastoma of the right nasal genal region, Histologic examination revealed that both lesions were constituted of spindle and stellate cells and a mino r amount of multinucleated giant cells in a myxoid stroma containing c isternal-like spaces. Immunohistochemical examination revealed positiv ity for vimentin in both cellular components. Ultra-structural examina tion showed, in some spindle and multinucleated cells, two kinds of in tracellular crystalline inclusions, located, respectively, in the cist ernae of the rough endoplasmic reticulum and, apparently free, in the cytoplasm. To the best of our knowledge, this case, unusual for its lo cation, is the first example of giant-cell fibroblastoma bearing intra cellular crystalline inclusions.