Meningioma with granulofilamentous inclusions

The authors report a case of intracranial meningioma with granulofilamentou s inclusions. A 50-year-old man had right trigeminal neuralgia due to trige minal nerve compression by a petroclival tumor and received tumor resection . Microscopically, tumor cells containing eccentric nuclei and intracytopla smic hyaline inclusions were arranged in sheets and whorls. The inclusions were negative for periodic acid-Schiff reaction. No histological anaplasia was seen. Immunohistochemistry showed epithelial membrane antigen reactivit y on the cytoplasmic membrane. Immunoreactivity for vimentin was recognized in cytoplasm adjacent to inclusions. However, confocal laser microscopic s tudy revealed immunoreactivity for vimentin even inside some inclusions. Ul trastructurally, interdigitation of cytoplasmic processes and desmosomes co nnecting adjacent cells were noted. Inclusions were composed of numerous fi ne osmiophilic granules attached by intermediates filaments. These findings were consistent with a meningioma with the granulofilamentous inclusions d escribed earlier. The findings demonstrated by confocal laser microscopy an d electron microscopy suggest that these granular materials may be the meta bolic products of vimentin filaments.