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Vilms's tumor

Almost all tumors of kidneys at children are provided by Vilms's tumor. It meets approximately identical frequency at children of both sexes irrespective of racial accessory and an incidence in a year (7,8:1 million children aged till 15 flyings).
Communication with congenital anomalies, most often with anomalies of urinogenital system (4,4%), a hemihypertrophy (2,9%) and with a sporadic aniridiya (1,1%) belongs to its important signs. Vilms's tumor develops at children, parents or sibsa of which suffer from a hemihypertrophy. It is accurate the last it can be shown only at teenage age therefore asymmetric growth at the child treated concerning Vilms's tumor should be considered as a hemihypertrophy rather than as complication after treatment.
Гистологические изменения при опухоли Вильмса
Fig. 1. Histologic changes at Vilms's tumor.
The epithelial component is provided rounded shape by tumoral tubules (also extended tumoral tubule is visible), a mesodermal component — strips of the extended kernels which are located in the cross direction.
Deletion of a chromosome 11 was for the first time revealed at relatives of children with a syndrome of an aniridiya of Vilms. It constantly is defined at the submicroscopic level in cells of the majority of tumors of Vilms even if the constitutional set of chromosomes remains normal.
As well as a retinoblastoma, a family form of a tumor of Vilms more often than sporadic, happens bilateral. Besides, at patients with bilateral, or hereditary, a form of an illness congenital anomalies are more frequent, and the tumor develops at earlier age. It is established that at the child, for one of parents of which it is diagnosed bilateral, or hereditary, Vilms's tumor, risk of its development makes 30%.
Pathology. The classical tumor of Vilms differs in solitary growth in any part of this or that kidney. It has a clear boundary and is usually encapsulated. The small centers of hemorrhages are typical. The tumor usually distorts a kidney contour, and the remained not changed its part quite often is squeezed and forms a thin rim around a tumor.
At microscopic examination in case of favorable histologic option it is possible to see both epithelial, and stromal elements (fig. 1). Distinguish three adverse histologic signs defined in 10% of tumors of Vilms, but in 60% of cases they cause a lethal outcome. Anaplaziya consists in noticeable variability of the sizes of kernels with abnormal mitotic figures. It with a bigger frequency occurs at children of the senior age groups. The Rabdoidny tumor consists of cells with fibrous eosinophilic inclusions; however presence of cells of true cross-striped muscles allows to exclude a rabdoidny tumor of Vilms. This its type often occurs at the most small children. Chistokletochny sarcoma of a kidney is characterized by spindle-shaped cells with the expressed vazotsentrichesky structure. It dominates at boys and often metastasizes in a bone.
The classification by stages used usually is offered by National group on studying of a tumor of Vilms. According to it in the I stage process is limited to a kidney and the tumor can be completely excised if the renal capsule of an intaktn, in the II stage a tumor extends out of kidney limits, but can be completely excised, in the III stage not hematogenous metastasises within an abdominal cavity appear, in the IV stage the tumor extends in the hematogenous way, is more often in lungs. In 5 — 10% of cases Vilms's tumor happens bilateral, and the survival of patients depends on extent of involvement in process of kidneys (the stage of V means a bilateral disease of kidneys). Relative number of patients with a tumor of the I—IV stage and the level of their survival are provided to tab. 1.
Table 1. Survival depending on a stage of a disease and histologic changes at the time of diagnosis, according to National researches at Vilms's tumor


Stage

Number
patients

Percent from total number

Percent of the children who survived during 2 flyings

1

371

28

89 — 92

11

377

28

83 — 93

III

383

29

75 — 87

IV

198

15

66 — 72

  And t about go.

1329

100

 

'Survivors during 2 flyings without recurrence. NG — adverse histologic signs.

Clinical manifestations. Middle age at the time of statement of the diagnosis makes about 3 flyings. Foreign education in an abdominal cavity, often asymptomatic is the most frequent sign. In most cases it smooth and firm, to the touch seldom crosses the average line. Its sizes widely vary, at the time of detection diameter made 11 cm. Education often is found at usual physical inspection or accidentally parents. Almost a half of children can have additional symptoms (abdominal pains or nausea, or that and another at the same time). In general patients with Vilms's tumor are slightly more senior and the general state them is broken less, than at an abdominal neuroblastoma.
Hypertensia is revealed at 60% of patients. It is caused by kidney ischemia, usually owing to the tumor pressure upon a renal artery, can be rather expressed, proceed is long and to lead to congestive heart failure.
Diagnosis. At any child at whom foreign education in an abdominal cavity is revealed it is necessary to suspect Vilms's tumor. At 10 — 25% of patients the micro and gross hematuria can be the only certificate that the tumor proceeds from a kidney. At an intravenous piyelografiya reveal intra renal localization of education. Differentiate generally with a neuroblastoma. The computer tomography is usually most informative. On the tomogram without contrasting it is possible to see that the usual tumor of Vilms proceeds from a kidney in the form of not homogeneous education with the sites of small density representing a necrosis. Sites of hemorrhages and small calcificats in general meet less often and are less expressed, than at a neuroblastoma. After an injection of a contrast agent the tumor is slightly contrasted. The clear boundary between it and an intact parenchyma, corresponding to a pseudo-capsule is often visible, the ellipsoidal area of the increased density corresponding to the squeezed unimpaired renal parenchyma is noted (see fig. 14-4, b). The computer tomography allows to establish an intra renal origin of a tumor on the basis of what exclude a neuroblastoma, to find multiple educations, to define distribution of a tumor and involvement in process of large vessels, to estimate a condition of a contralateral kidney. The important problem at differential diagnosis is represented by a hydronephrosis, a cystosis of kidneys, a mesoblastic nephroma and other malignant diseases of kidneys, for example a cellular carcinoma, sarcoma and a lymphoma.
Metastasises in lungs come to light on roentgenograms at 10 — 15% of patients by the time of statement of the diagnosis i.e. more often than at a neuroblastoma. The computer tomography of a thorax is informative, especially at visualization of parts of lungs there is lower than the level of dome of a diaphragm (fig. 2). At patients with suspicion on metastasises of a liver it is necessary to carry out its radio isotope scanning. Bones and marrow investigate only after surgical intervention and only if histologic symptoms of a tumor are adverse, and the patient is disturbed by constant pains.
Some seldom found paraneoplastic syndromes can be connected with Vilms's tumor. The neoplasm can produce erythropoetin that leads to an erythropolycythemia. There are messages on a secondary hypercalcemia.
Treatment. Usually immediately delete a kidney with the tumor which developed in it even if there are metastasises in lungs. During operation it is necessary to carry out careful audit of a contralateral kidney to exclude bilateral process, and a liver to exclude metastasises. Audit of retroperitoneal lymph nodes and renal veins is made with the purpose to define whether they are involved in pathological process. It is necessary to try to remove a tumor with the uniform block, but as himio-and a roentgenotherapy during the postoperative period promote destruction of its remains, its full excision is not recommended if it threatens the patient's life.

Fig. 2. Vilms's tumor. The computer tomography of a thorax allowing to see lower metastasises than a diaphragm dome which is difficult for differentiating at a X-ray analysis.
Опухоль Вильмса
Vilms's tumor is sensitive both to himiopreparata, and to beam influence. Logical and systematic treatment was developed in connection with formation in 1969 of the joint group of National researches (NWTS). Till this time practically all patients during the postoperative period were exposed to a roentgenotherapy and treatment by one himiopreparat according to different schemes. The NWTS group reported that the combined treatment by Vincristinum and Actinomycinum has a clear advantage before treatment only by one drug at patients with the localized forms of a disease and that doxorubicine serves as important addition to treatment at far come process. Besides, it was shown that it is optional to carry out a roentgenotherapy to the I stage of a disease, to the patient in this case the short course (6 months and less) the combined chemotherapy is sufficient. Now optimum doses and fields of radiation at patients in II and in the III stages of a disease receiving himiopreparata are studied. At the IV stage of a disease the X-ray-chemotherapy is recommended by three or four drugs within 15 months.
Preoperative treatment is not recommended for patients with unilateral process, but it can be treatment of the choice at a bilateral tumor as when wrinkling primary tumor it is possible to make a partial nephrectomy and preservation as it is possible the bigger volume of intact renal fabric. Patients with a bilateral tumor with a renal transplantation usually had no effective bilateral nephrectomy.
Forecast. In general the forecast is more favorable at children whose age at the time of statement of the diagnosis does not reach 2 years and who have a mass of a tumor less than 250 g. Histologic changes and a stage of process belong to the most significant predictive signs. Any recurrence means the adverse forecast.
Value of involvement in process of lungs is insufficiently estimated. Metastasises in them which can be removed should be deleted.

 
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