Schwannoma overview
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Schwannoma Microchapters |
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Schwannoma overview On the Web |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Maneesha Nandimandalam, M.B.B.S.[2]
Overview
Historical perspective
Classification
Schwannoma may be classified according to pathology into 4 subtypes: conventional schwannoma, cellular schwannoma, plexiform schwannoma, and melanotic schwannoma. Based on location it is classified into intracranial schwannoma,Acoustic neuroma (most common),trigeminal schwannoma, facial nerve schwannoma, jugular foramen schwannoma, hypoglossal schwannomas, spinal schwannoma, intercostal nerve schwannoma, intramuscular schwannoma, posterior mediastinum schwannoma, retroperitoneum schwannoma, intracerebral schwannoma.
Pathophysiology
Schwannomas may arise sporadically or in association with Neurofibromatosis type 2 as a result of mutations involving merlin protein. Loss of function of a tumor suppressor gene called merlin gene is noted commonly. Schwannomas are composed of spindle cells which demonstrate two growth patterns Antoni type A and Antoni type B. Antoni type A patternin which elongated cells are densely packed and arranged in fascicles. Palisades are sometimes seen, when prominent these form verocay bodies. Antoni type B pattern cells are less compact and are prone to cystic degeneration. Schwannoma variants include ancient schwannoma, cellular schwannoma, melanotic schwannoma, plexiform schwannoma. Immunohistochemistry positive for S100, collagen IV, CD34, neurofilament protein, podoplanin, calretinin, Sox10. Associated conditions include neurofibromatosis type 2, schwannomatosis, carney's complex.