RETINOBLASTOMA (late lat. retina a retina + Greek blastos a sprout, a germ + - oma) — the malignant tumor developing from a retina. Arises, as a rule, at children under 3 years. R.'s frequency makes about 1 case on 15 — 34 thousand live-born.
Defeat can be one and bilateral. Unilateral R. usually develops as a result of the vegetative mutations striking only retinal cells. Bilateral tumors arise more often because of mutations of chromosomes of sex cells and can be combined with a nanocephalia, not fusion of the sky, psychomotor frustration, etc.
Microscopically distinguish the differentiated and undifferentiated forms of a tumor. Specific structure of the differentiated R. are true «sockets» (tsvetn. fig. 13), to-rye consist of a cylindrical form of neuroepithelial cells of embryonal type; the abortal forms of outside segments of photoreceptors, existence are sometimes had to-rykh it is confirmed with researches at the electronic and microscopic level. At undifferentiated forms of a cell small, with a big kernel and a narrow rim of cytoplasm, they are located diffuzno or form around vessels of «pseudo-socket», surrounded with a zone of necroses and calcificats (tsvetn. fig. 14). In a tumor mitoses are often noted, dissimination develops in a vitreous and in an anterior chamber of an eyeglobe. Then the tumor infiltrirut covers of an eyeglobe.
Early the wedge, unilateral R.'s sign is squint (see), bilateral — nystagmus (see). Leykokoriya, or the so-called amaurotic cat's eye which is shown a mydriasis and its yellow luminescence as a result of reflection of light the tumoral masses located in a vitreous treats late symptoms of a disease when already most part of an eyeglobe is filled with tumoral masses (tsvetn. fig. 9).
Distinguish four stages of a course of a disease. In the first stage one or several retinal whitish-pink centers, with a smooth or uneven relief, neogenic vessels and gray sites of calcificats appear. The sizes of a tumor do not exceed one quadrant of an eyeground, surrounding fabrics are not changed (tsvetn. fig. 12). In the first stage the small tumor is revealed almost always accidentally at routine maintenances. In the second stage intraocular dissimination is noted what whitish inclusions of the different sizes in a vitreous, pretsipitatopodobny deposits in a corner of an anterior chamber of an eyeglobe and on a back surface of a cornea testify to (tsvetn. fig. 15). Are a consequence of the specified changes secondary glaucoma (see), buftalm (see. Hydrophthalmia ; tsvetn. fig. 10). In the same stage at germination amotio of a retina can occur a tumor of a retina and accumulation of transudate under it (tsvetn. fig. 11). Sight gradually decreases to a total blindness. In the third stage there is an extraocular spread of a tumor. At the same time germination in an eye-socket is followed exophthalmos (see); germination in a head cavity, most often on an optic nerve (tsvetn. fig. 16), is followed by symptoms of damage of a brain (a headache, nausea, vomiting, etc.). R.'s germination in choroid of an eye (see), differing in rich blood supply, is an adverse predictive sign since leads to a hematogenous disseminirovaniye. As a result of a necrosis of a tumor toxic can develop uveitis (see). In the fourth stage the symptoms caused by the hematogenous innidiation continued by growth in bones of a skull and a brain join eye manifestations.
Diagnosis The river is based on data oftalmoskopiya (see), ultrasonic and rentgenol. researches (see. X-ray analysis , Ultrasonic diagnosis ). Oftalmoskopiya at children with R. will be seen off under anesthetic or in a condition of a deep sleep. An informative diagnostic method, especially at opacification of the refracting environments, ultrasonic investigation is, with the help to-rogo reveal calcificats and zones of a necrosis in a tumor that allows to foresee cellular structure of a new growth, and also measure a vystoyaniye of a tumoral node. Rentgenol. R.'s diagnosis is based on detection of calcificats in a tumor. At a X-ray analysis of bones of a skull expansion of the channel of an optic nerve (the visual channel, T.) confirms germination of a tumor out of limits of an eye-socket. In blood the increased maintenance of the general glycoproteins is noted.
In the first and second stages at the small tumors which are located outside macular and peripapillary area organ-preservation cryoapplication is possible (see. Cryosurgery ). It is most radical enucleation of an eye (see) with a resection of an optic nerve at distance of 10 — 15 mm from a back pole of the eyeball. Is of great importance for the choice of a further method of treatment morfol. a research of distal department of an optic nerve after enucleation. At germination in an optic nerve through cutting off and dissimination on its covers (to outside and internal vaginas, T.) carry out the combined treatment after operation: roentgenotherapy (see) and chemotherapy (see. Chemotherapy of tumors ). Use of cyclophosphamide (Cyclophosphanum) and Prospidinum allows to lower twice a total exposure dose during the carrying out radiation therapy (see) that is especially important at the bilateral defeat differing in a frequent recurrence. At bilateral defeat the combined treatment is shown: rentgeno-and chemotherapy, photocoagulation (see. the Laser, lasers in ophthalmology ), cryotherapy (see), a podshivaniye of radioactive disks, removal of the most struck, unpromising eyeglobe for sight.
Forecast it is favorable at tumors in the first and second stages which resulted from vegetative mutation. In the third stage at infiltration by a tumor of an intraocular part of an optic nerve to a trellised plate of a sclera the risk for life makes apprx. 15%, at further distribution of process on an optic nerve, W. h and out of limits of entry into it of the central artery of a retina, risk makes 44 — 65%. Approximately at 10% of patients with bilateral defeat in the radiation zone development of various tumors, most often is possible sarcomas (see), rhabdomyosarcomas (see), etc.; in some cases develops leukosis (see).
At the healthy parents having one child with R., probability of development of a tumor in the subsequent children apprx. 6% (vegetative mutation). If in a family several children are sick, the risk of development of R. in the subsequent children increases to 50% since in this case the autosomalny dominant form is inherited. At children of the patients cured of a hereditary form P., possibility of a tumor makes apprx. 50%. All subsequent children since the birth shall be in families where there is a child with R., under dispensary observation, also as well as children, to parents to-rykh treatment concerning River was carried out.
Bibliography: Dybov S. A retinoblastoma, the lane with bolg., Sofia, 1975; Kowalewski E. I. Eye diseases, M., 1980; Paches A. I., Brovkina A. F. and 3 and and N of and r about in and G. G. Clinical oncology of an organ of sight, M., 1980; Char D. N of Current concepts in retinoblastoma, Ann. Ophthal., v. 12, p. 792, 1980, bibliogr.; T s’ about M. O., Fine B. S. a. Zimmerman L. E. The nature of retinoblastoma, Amer. J. Ophthal., v. 69, p. 339, 350, 1970.
G. G. Ziangirova.