From Big Medical Encyclopedia

PARAFIZALNY CYST (grech, paraphysis growth, cyst; synonym: monroye-cyst, pleksus-cyst, neuroepithelial cyst, ependimalny cyst) — colloid cyst of the third cerebral cavity. Meets seldom, making 0,55% of all tumors of a brain.

Fig. 1. Macrodrug of the left half of a brain (interior): the arrow specified a parafizalny cyst of the III ventricle.

P. is macroscopic to. represents a single-chamber thin-walled cavity of rounded shape to dia, from 1 to 3 cm, up to 9 cm less often and more, occupying preferential front and upper parts of the third ventricle and quite often attached to a vascular texture in the forefront of a roof of a ventricle (fig. 1). The cavity of a cyst is executed by jellylike contents of greenish, yellowish or grayish color.

Fig. 2. Microdrug of a wall of a parafizalny cyst: 1 — a cylindrical epithelium; 2 — the subject collagenic stroma; coloring hematoxylin-pikrofuksinom; X 800.

Microscopically the wall of a cyst is presented by the collagenic fibers, places hyalinized with availability of infiltrates (lymphocytic or from polinuklear). Layer of collagenic fibers inside is bordered single-layer (more rare multilayer) with an epithelium of a cylindrical, cubic form, sometimes with existence of cilia (fig. 2). Between the cells supplied with cilia the cells producing a secret are located.

Etiology and pathogeny colloid cysts are not specified. Shyovall (E. S j ovali, 1909), Mac Lane (And. J. McLean, 1936), Moss (L. D. Moss, 1945), Wilson (A. A. Wilson, 1946) consider a source them iarafiz — that the Tax Code about the wall embryonal cavity representing protrusion of a roof of the third ventricle behind interventricular (monroye-vy) foramens, Bailey (P. Bailey, 1916), Tsyulkh (To. J. Zulch, 1956) — an ependyma, and Heymeyker and Dzhenarmen (W. Haymaker, Jenarmen, 1955) — a vascular texture. The opinion on an origin of colloid cysts from a paraphysis is based on existence of these educations in the third ventricle, however similar cysts meet in side and the fourth ventricles and in a transparent partition. Nek-ry researchers consider an epithelium of colloid cysts ectopic, coming from upper respiratory tracts. Such point of view is confirmed by N. R. Ghatak with soavt, in 1977 electronic microscopic examination of a colloid cyst.

For clinical picture existence is most characteristic occlusal syndrome (see) with sudden emergence of attacks of headache in connection with change of position of the head and trunk. Such attacks quite often are followed by disturbance of consciousness, drowsiness, decrease in sight.

For the first time the intravital diagnosis of a colloid cyst of the third ventricle was made At. The dandy with the help ventrikulografiya (see), at a cut the occlusal hydrocephaly caused by closing of interventricular foramens was revealed. At diagnosis use the slowed-down directed pneumoencephalography (see), a positive ventrikulografiya, a computer tomography (see. Tomography computer ). The differential diagnosis on the basis a wedge, symptoms is very difficult.

Treatment of colloid cysts — only surgical.

The forecast at the uncomplicated course of operation favorable.

Bibliography: Egorov B. G. and Konovalov Yu. V. To a question of diagnosis and surgical treatment of cystous tumors of the III ventricle, Vopr, neyrokhir., t. 4, No. 1-2, page 45, 1940; Uspenskaya O. S. Clinic of primary tumors of the III ventricle, in book: Probl, sovr, neyrokhir., under the editorship of B. G. Egorov, t. 3, page 189, M., 1959; Dandy W. E. Benign tumors in the third ventricle of the brain diagnosis and treatment, Springfield, 1933; G h a-t a k N. R., Kasoff J. Alexander E. Further observation in the fine structure of a colloid cyst of the third ventricle, Acta neuropath. (Berl.), v. 39, p. 101, 1977; Weinberger L. M. a. Boshes B. Paraphysial cysts of the third ventricle, Surgery, v. 13, p. 368, 1943.

I. A. Brodskaya.