The electron microscopic spectrum of nerve sheath tumors.

In summary, nerve sheath neoplasms have a wide spectrum of histological and ultrastructural appearances. The diagnosis of classical schwannomas can usually be made with confidence by light microscopy alone, but cellular schwannomas, malignant schwannoma, special types of schwann cell neoplasma (pigmented, epithelioid, granular cell), desmoplastic amelanotic melanomas, and neurofibromas should all be studied by electron microscopy if the cell type is to be established with certainty. It is our experience and impression that a high level of diagnostic accuracy can be accomplished by this technique in all but a few of the cellular and pleomorphic (probable) schwann cell tumors, and in many of the neurofibromatous tumors.