MENINGIOMA (meningioma, grech, meninx, meningos a meninx + - oma; synonym: fungoid tumor of a firm meninx, fibroendothelioma, meningotelioma, arakhnoidendotelioma, arachnoidal meningioma, meningeal fibroblastoma, meningoblastoma) — extra brain, in most cases the benign tumor, coming from firm, is more rare than a soft cover of a head or spinal cord, is rare from a vascular texture of brain ventricles or arising ectopically in bones of a skull, a backbone and on the course of nervous roots.
In a literal sense M. — a tumor of a meninx. However the term «meningioma» it is accepted to designate only the tumors coming from cover cells (arakhnoidendoteliya) of a web leaf, and also, presumably, from polyblastic mesenchymal cells of a vascular leaf of a soft meninx. A variety of places of initial growth of M. is explained by embriogenetichesky and space proximity of laying of a soft and firm meninx, bones of a skull and backbone, existence of pakhionovy granulations and intradural cellular spots, the containing arakhnoidendoteliya, participation of a soft meninx in formation of a stroma of a vascular texture, eliminating of a soft meninx in covers of nervous roots.
Intracranial M. make 13 — 19% of all intracranial tumors; M of covers of a spinal cord meet less often, but among spinal tumors win first place. M. more often on average and advanced age are found.
On localization distinguish: 1. M of covers of a brain: 1) konveksitalny; 2) parasagittal — meets along the corner formed by a wall of an upper longitudinal sine and a firm meninx of a convex surface of big hemispheres; can squeeze a sine or grow into it; 3) big crescent shoot; 4) tentorial; 5) firm meninx of the basis of a brain: a) a front cranial pole — an olfactory pole, a hillock of the Turkish saddle; b) an average cranial pole — wings of the main bone; c) a back cranial pole — a blyumenbakhov of a slope, edge of a big occipital opening. 2. M of covers of a spinal cord. 3. Intra ventricular M., coming from vascular texture. 4. Extradural M. — proceeds from periblasts of a firm meninx, often infiltrirut adjacent bones of a skull, a wall of the vertebral channel. The m connected with covers of an optic nerve are located in the visual channel, in a cavity of an orbit. 5. Ectopic M. — meets in bones of a skull and a backbone, in adnexal nasal cavities, in cavities of an inner and middle ear, on the course of nervous roots.
M. usually is microscopic represents well delimited node of a rounded or ovoidny shape (fig. 1) quite often soldered to an inner surface of a firm meninx. Also flat nodes meet. Spinal M. more often oblong, at an extradural arrangement can cover the coupling a dural bag. In size M. vary in the diameter from several millimeters to 15 cm and more. M.'s consistence quite dense, especially at abundance of fibrous fabric. In most cases the tumor is surrounded with the dense capsule. On a section fabric M. gray or meat - red, at the plentiful maintenance of so-called ksantomny cells accepts ocherous coloring. Existence of cysts in M. is not characteristic.
M usually of an odinochna, but can be and multiple. In rare instances multiple M. is combined with a multiple neurinoma — a disease of Recklinghausen (see. Neurofibromatosis ).
Gistol, M.'s classifications do not differ significantly one from another. According to histologic classification of tumors of c. N with. the accepted Commission of WHO on tumors of a brain (Geneva, 1976), allocates the following subtypes M.:
1. Meningoteliomatozny M. (endoteliomatozny, syncytial, arakhnoidendoteliomatozny). Consists of the mozaikopodobno-located monomorphic cells with the oval or roundish kernel containing moderate amount of gentle grains of chromatin. The stroma is presented by not numerous vessels and rare thin tyazha of connecting fabric bordering cellular fields. Are characteristic, but concentric structures, similar to the cut bulb, from the flattened tumor cells accumulating one on another not always meet. The hyalinized center of such structure quite often obyzvestvlyatsya (a so-called psammous little body).
2. Fibrous M. (fibroblastichesky). It is constructed of fibroblastopodobny cells, to-rye are located in parallel each other and develop in the bunches intertwining among themselves containing connective tissue fibers (fig. 2). Kernels of cells extended. Concentric structures, psammous little bodies can meet.
3. The transitional M. (mixed). Includes meningoteliomatozny and fibrous M.'s structures
4. Psammomatozny M. — mengigoteliomatozny or fibrous M. with a large number of psammous little bodies.
5. Angiomatous M. — the meningoteliomatozny or transitional (mixed) M. differing in exclusively plentiful vascularization.
6. Gemangioblasticheskaya M. is identical to a hemangioblastoma — to an angioretikulema (see)
7. Gemangioperitsitarny M. is identical to a gemangioperitsitoma (see) others of bodies.
M., on gistol, the transitional forms presenting to structure between gemangioblastichesky and gemangioperitsitarny meet. On this basis it is suggested about their homogeny from polyblastic mesenchymal cells of a meninx.
8. Papillary M. Isklyuchitelno rare option. The papillary structure simulates a carcinoma.
9. Anaplastic M. (malignant). It is characterized by the increased number of cells per acre, cellular polymorphism, frequent mitoses, aggressive, infiltriruyushchy growth. From gistol, signs of a zlokachestvennost probably most informatively in the predictive relation a combination of an unusual plotnokletochnost, the increased mitotic activity and, perhaps, infiltrative growing into bark while nuclear polymorphism, necroses, the strengthened vascularization taken in itself, the same as, apparently, have no one existence of figures of a mitosis, predictive value. Anaplastic M. not often meet, their transition to meningeal sarcoma — the tumor which is coming from cellular elements of a firm or soft meninx and having expressed morfol, and biol, signs of a zlokachestvennost, histologically representing a fibrosarcoma, polymorphocellular, undifferentiated sarcoma is even less often observed.
From dystrophic changes in M. the hyalinosis of walls of vessels, the centers of concentric structures, adjournment of salts of lime in psammous little bodies, in vascular walls especially often meet. Are less often observed mucoid dystrophy of tumor cells, sometimes with formation of small cysts, accumulation in cells of holesterinester («ksantomny», «foamy» cells). In M.'s most in different proportions the structures characteristic of separate gistol, subtypes (fig. 3) are combined. The diagnosis is made on the prevailing structure. Meet meningoteliomatozny more often, then transitional (mixed) M. Meningoteliomatoznye M. develop preferential from covers of a convex surface of a great brain, fibrous — prevail in suprasellyarny area and a back cranial pole, psammomatozny — in a cavity of the vertebral channel.
Apparently, there is no communication between gistol, a subtype M. and speed of its growth. The exception is made gemangioperitsitarny and anaplastic M., growing probably quicker than other subtypes.
M. usually expansive grows, being only pressed into adjacent marrow. However in nek-ry cases under a microscope on edge of a tumor it is possible to see superficial outgrowths of its fabric in the tissue of a brain adjoining on a tumor. Formation of hyperostoses in a bone, adjacent to a tumor, quite often infiltrirovanny tumor cells is characteristic. M.'s innidiation is observed extremely seldom.
Wedge. high-quality M.' current slow, duration of a disease is quite often estimated many years.
The symptomatology can be various; as a rule, primary and focal symptoms are observed (see. Brain, tumors ).
M.'s treatment operational.
The forecast is defined by completeness of an oncotomy. A recurrence is rather frequent, a source to-rykh are the small tumoral ochazhka difficult available to the surgeon put in the subject firm meninx or a bone of a matrix of the main tumoral node removed on operation.
Bibliography: Krasovsky E. B. Arakhnoidendoteliomy of the central nervous system, M., 1958; The Multivolume guide to pathological anatomy, under the editorship of, A. I. Strukova, t. 2, page 376, M., 1962; Smirnov L. I. Tumors of a head and spinal cord, page 119, M., 1962; Stanislavsky B. G. Meningiomas of a back cranial hole, Kiev, 1976, bibliogr.; Tushevsky V. F. About malignant regeneration of meningiomas, Vopr, neyrokhir., century 6, page 18, 1959, bibliogr.; Bailey O. T. Histologic sequences in meningioma, with consideration of nature of hyperostosis cranii, Arch. Path., v. 30, p. 42, 1940; Cushing H. E i sen ha r d t L. Meningiomas, Springfield, 1938; H e n-s with h e n F. Tumoren des Zentral nerven-systems und seiner Hiillen, Handb. d. spez. path. Anat. Histol., hrsg. y. O. Lubarsch u. a., Bd 13, T. 3, S. 413, B. u. a., 1955, Bibliogr.; R a n d R. W. Microneurosurge-ry, St Louis, 1969; Z ii 1 with h K. J. Die Hirngeschwiilste in biologischer und mor-phologischer Darstellung, S. 146, Lpz., 1956.
B. B. Arkhangelsk, I. A. Brodskaya.