Nerve Sheath Cells Research Articles

Degenerate Neurilemmoma: A Diagnostic Problem

In 1935 Stout delineated the clinical and pathological features of the nerve sheath tumour neurilemmoma (also known as schwannoma, lemmocytoma, neurinoma, acoustic neuroma and perineurial fibroblastoma). Although originally considered rare this is a lesion frequently encountered in surgical pathology and usually one which is recognised by its typical histological features. The neurilemmoma is a true neoplasm believed by most investigators to derive from nerve sheath cells of Schwann and thus to be of neuroectodermal origin (Murrayand Stout 1940). A few workers still favour derivation from perineurial fibroblasts (Cravioto 1966, Santhaveerappa and Bourne 1966). The typical tumour is usually solitary, encapsulated well circumscribed and adjacent to recognisable nerves. It shows Antoni A areas, the cellular regions; and Antoni B areas, the myxomatous regions,as well as so called Verocay bodies which are zones of collagen surrounded by palisading nuclei. The solitary type neurilemmoma gives no diagnostic problem usually, but the subvariety composed of thick vessels, hypercellular areas with nuclear atypism, and degenerative foci is apparently confusing to pathologists and prompted our investigation. This variant has been termed degenerate or ancient neurilemmoma (Ackerman and Taylor 1951).

Studies on experimental malignant nerve sheath tumors maintained in tissue and organ culture systems. III. Melanin pigment and melanogenesis in experimental neurogenic tumors: a reappraisal of the histogenesis of pigmented nerve sheath tumors.

Four melanin pigment-containing intracranial tumors were found in three Long-Evans rats in the course of experimental oncogenesis by transplacental ethylnitrosourea (ENU). One of them was a leptomeningeal melanoma. Aside from the presence of scattered melanin-pigmented cells, the other three had the typical histological features of ENU-induced malignant nerve sheath tumors. Two of the three tumors were studied by electron microscopy and in tissue and organ culture systems. One of them demonstrated progressive melanogenesis in vitro; the other failed to produce more melanin and showed increasing differentiation, with a Schwannoma-like pattern by light microscopy. Melanosomes and premelanosomes were identified in both tumors by electron microscopy; the other fine structural features were those of malignant Schwannomas. These observations are relevant to the controversy on the histogenesis of pigmented nerve sheath tumors occasionally encountered in man and on the relationship of these tumors to pigmented nevi. The findings in the present study support the view of Masson that neoplastic nerve sheath cells are capable of melanogenesis.

TRANSTEMPORAL BONE MICROSURGICAL REMOVAL OF ACOUSTIC NEUROMAS. THE PATHOLOGY OF ACOUSTIC NEUROMAS.

Acoustic are encapsulated tumors which, after numerous stormy controversies, are now generally agreed to arise as the result of neoplastic proliferation of the neurilemmal or Schwannian nerve sheath cells of the eighth cranial nerve, usually the vestibular division, within the internal acoustic meatus. The currently preferred names for this specific nerve sheath tumor, as Stout has termed it, are neurilemmoma or benign schwannoma. The following brief consideration of the history and cellular origin of this group of neoplasms, the incidence and sites of predilection of intracranial and intraspinal neurilemmomas, and the gross and generously illustrated microscopic appearance of acoustic are intended to round out this monograph dealing with an important, benign, and operable intracranial tumor. History and Cellular Origin These tumors were called neuromas by Virchow who recognized them only as a specific form of acoustic nerve tumor. Verocay described the peculiar bodies formed within these lesions

Neurofibroma of the Cauda Equine: Report of a Case

Primary neoplastic lesions arising from the spinal cord, nerve roots, and meninges comprise about 15 per cent of all central nervous system tumors. Among 35,000 autopsies in Vienna, Schlesinger (1898) recorded 994 tumors of the central nervous system, of which 151 were spinal cord neoplasms. Ewing (1931) collected 400 spinal cord tumors; out of that number 37, or 9 per cent, were neurofibromas. Peers (1936) found 4 intra-medullary spinal cord tumors in 10,592 autopsies. Adson (1939) reported 557 intraspinal neoplasms; 163 of these, or 29 per cent, were neurofibromas. Of 275 spinal cord tumors removed surgically, Elsberg (1941) classified 59 as perineurial fibroma or neurofibroma. Of these, 54 were intradural neurofibromas; only 5 were extradural. The case to be reported here represents a simple intradural circumscribed neurofibroma originating from the cauda equina, in a young soldier, recognized preoperatively and classified chiefly through the medium of myelography with Pantopaque. Grossly, a neurofibroma is a circumscribed, encapsulated lesion, varying in size, arising from nerve-sheath cells. It may be single or multiple, benign or malignant, simple or plexiform, and may involve either the central or peripheral nervous system. Microscopically, elongated cells are demonstrable, showing a parallel arrangement of their nuclei, called palisading. Occasionally this tumor may show degenerative cystic change. If it arises from the perineurial connective tissue it is called a perineurial fibroblastoma. It may occur at any age, but single lesions are more common in the earlier age group. If it develops within the spinal canal, its symptoms depend on its location, size, and the amount of pressure it exerts on the spinal cord or nerve roots. It may be intradural or extradural, may be globular, bulbous, fusiform, or dumb-bell shaped. Neurofibromas of the cauda equina are less common than similar tumors in other parts of the spinal canal. They may occasionally reach large size, producing extensive bone destruction involving several vertebral segments. Case Report A 23-year-old soldier was inducted into the Army about two months prior to admission to the hospital. Five years earlier, after an effort of lifting, he experienced low-back pain. This had recurred on several occasions following similar effort. Two years before admission a severe attack followed a fall on the back, from a low truck. The attacks lasted two to three weeks, but in the long intervals between attacks the patient was relatively free of discomfort and able to carry on his routine duties on the farm. The attack was in the nature of a severe burning pain in the lumbosacral region, radiating to the right side of the scrotum, and the anteromedial aspect of the right thigh, with inconstant numbness and tingling sensations in the lateral aspect of the right thigh and muscle twitching in that region.

An experimental study of the origin of the meninges.

As a result of experimental work concerning the healing of the meninges following injury, it was found by one of us (S. C. H),1 that the dura in the presence of an intact lepto meninx heals without adhesion to the underlying membrane. This is brought about, not by the ingrowth of mesothelium from the surrounding normal dura, but by the direct transformation of mesenchymal cells into mesothelium which comes to lie against the uninjured and impervious lepto-meninx.On the other hand,2 when the lepto-meninx is injured with the overlying dura remaining undamaged, an analogous healing without adhesions does not take place. The lining mesothelium of the dura disappears and this membrane enters intimately into the reparative process in the subjacent lepto-meninx, the final result being dense adhesions. This seems to indicate some fundamental histogenetic difference between these two structures.Harrison3 has shown by experimental methods that the nerve sheath cells are derived from the neural crest. Inasmuch as th...