Myxoid meningioma: histochemistry and electron microscopy.

Two meningiomas were investigated that consisted largely of myxoid tissue. Staining with Alcian blue and incubation with staphylococcal, Streptomyces or testicular hyaluronidase revealed that the matrix of the myxoid tissue contained hyaluronic acid and chondroitin sulphate. Special fixation was used for ultrastructural preservation of the myxoid matrix, and its ultrastructural appearance was that of these glycosaminoglycans. The previous appellations of microcystic or vacuolated meningioma applied to this type of meningioma relate apparently to poor preservation of myxoid tissue.