Microcystic meningioma. A case report.

Microcystic meningioma is a distinct morphological variant of meningioma, characterized by loose texture and microcysts with formation of large extracellular spaces containing edematous fluid. The tumor cells have stellate and vacuolated cytoplasm with long cytoplasmic processes. We experienced a case of typical microcystic meningioma occurring in the falx cerebri adjacent to the left superior parasagittal sinus in a 41-year-old man. The tumor showed the typical histologic features with a few nests of meningothelial whorls. The tumor cells showed diffuse immunoreactivity for vimentin, epithelial membrane antigen (EMA), and S-100 protein. Ultrastructural study confirmed the meningiomatous nature of the tumor.