Microcystic variant of meningioma

Abstract
Meningiomas occasionally show small areas in which the cells are stellate with slender processes surrounding microscopic spaces, giving a lace-like appearance to the tissue. In the case of a 52 yr old woman with a tumor rising from the falx, virtually the entire tumor was composed of lacy reticulated tissue. Most of the tumor cells had processes that stained blue with phosphotungstic acid hematoxylin, suggesting the appearance of a glioma. However, EM showed that the extracellular space was extensive, and the tumor cells had long cytoplasmic processes which formed interdigitations with one another. Desmosomes were numerous. The immunoperoxidase method for glial fibrillary acidic protein gave negative results. This tumor apparently was a microcystic variant of meningioma.