Reticulin fiber staining of crush preparations for the rapid differentiation between schwannomas and meningiomas.

The use of reticulin fiber staining of cytologic crush preparations for the rapid differentiation of schwannomas and meningiomas of the cerebellopontine angle was studied. As in paraffin-embedded sections, the reticulin stain demonstrated distinctly different patterns in the two types of tumors. Schwannomas showed extremely numerous, uniformly delicate straight fibers in a streaming or interlacing pattern in cellular areas and less dense, more wavy or curly fibers in degenerative areas. Fibroblastic meningiomas showed a few loose fibers of variable thickness in a root-like tangle while meningotheliomatous meningiomas showed no fibers, except in areas of fibrovascular stroma; both types showed small scattered round structures made up of reticulin fibers. These findings suggest that reticulin staining of crush preparations should be performed as an adjunct to routine cytologic staining of crush preparations and the study of frozen sections in making the intraoperative diagnosis of these tumors.