Schwann cell versus fibroblast as the origin of the specific nerve sheath tumor: Observations upon normal nerve sheaths and neurilemomas in vitro.

Since the description by Verocay 1 in I908 of the specific nerve sheath tumor which he named neurinoma, two opposing views of its cellular origin have prevailed. One, represented by the work of Nageotte,2 3 4 and of Masson,5 is based on the study of the morphology and physiology of normal nerve sheaths under various experimental conditions. By comparing the histology of these tissues with that of the tumors, these workers feel that they have proved that the tumor originates from the sheath of Schwann. They therefore give it the name schwannoma, or peripheral glioma. The opposing opinion, represented by the work of Mallory 6 and of Penfield,7 emphasizes mainly the study of the extracellular components of these tumors, and rests on the assumption that collagen and reticulin can be formed only by cells of mesodermal derivation. Since the tumors contain considerable collagen and reticulin, this line of reasoning induces the conclusion that the tumors are derived from the endoneural or perineural components of the nerve sheath, and the term perineural fibroblastoma is adopted. Both schools accept Harrison's 8 demonstration in I924 of the origin of Schwann cells from the neural crest. Since neither side has been able to convince the other by histological methods, and since in some instances the same evidence is interpreted differently by exponents of opposing theories, an attempt has been made in this laboratory to solve the problem by