Medulloblastoma (medulloblastoma) — the malignant tumor from medulloblast, unripe cages of a glia which is localized usually in a worm of a cerebellum which is near the fourth ventricle of a brain. Symptoms of cancer intoxication, the accruing intrakranialny hypertensia and a cerebellar ataxy are characteristic. The diagnosis is made on the basis of a clinical picture, results of the analysis of cerebrospinal fluid, PET, KT or MRT, a biopsy. Treatment includes surgical removal of a tumor, restoration of normal circulation of cerebrospinal fluid, beam and chemotherapy.
Medulloblastoma (a granuloblastoma, a neuroglioma embryonic, a glioma sarkomatozny) — very malignant pathology of a back cranial pole. The tumor, as a rule, is in a worm of a cerebellum, and at children is more senior than six years can be localized in hemispheres of body. Medulloblastoma usually quickly spreads on likvorny ways, than differs from other tumors of a brain.
7-8% of total number of volume educations, known in neurology, among brain tumors in pediatrics — 30% fall to the share of a medulloblastoma. Medulloblastoma is on the second place on frequency among brain tumors at children. Prevalence of this type of new growths – 1,5-2 cases on hundred thousand. Develops at boys, in comparison with girls more often (a ratio 65/35).
Typical age when find medulloblasty, five-ten years. But it not only "children's" pathology, reveal it at any age. Children make ¾ from total number of patients of medulloblastomy. This tumor occurs at adults usually aged from 21 up to 40 years.
Usually medulloblastoma cases — sporadic. However there are hereditary diseases associated with high risk of development of this tumor. Treat them: Rubenstein-Teybi syndrome, Gorlin's syndrome, Tyurko's syndrome and syndrome of a blue nevus.
Why the medulloblastoma develops, today remains not clear. Only risk factors of this pathology are known, belong to them: age up to 10 years, action of ionizing radiation, influence of carcinogens of food, varnishes, paints, household chemicals; the viral infections (a cytomegalovirus, VPCh, infectious , herpetic infections) damaging a genome of cages; the burdened heredity. Medulloblastoma is a primitive neyroektodermalny tumor (PNET). Usually it is located subtentorialno, that is under mashed a cerebellum, quickly sprouts in his worm and fills all fourth ventricle of a brain. It leads to blocking of a likvoroottok as the tumor increasing in sizes blocks ways of circulation of cerebrospinal fluid. Intra cranial pressure at the patient sharply increases that is shown by a syndrome of the expressed intrakranialny hypertensia. Defeat of bulbarny departments arises at late stages of a disease due to germination of a tumor in a brain trunk.
The histologic picture of a medulloblastoma represents concentration of the small, roundish, low-differentiated, proliferating embryonic cages with very thin cytoplasm and a hyperchromic kernel.
This malignant tumor in 80% of cases arises in a worm of a cerebellum, and in 20% — in its two hemispheres. On a histologic structure distinguish the following types of a new growth:
- Medullomioblastoma containing muscle fibers in structure
- Melanotichesky medulloblastoma which consists of the neyroepitelialny cages having melanin in structure
- Lipomatozny medulloblastoma in which there are fatty cages (the most good-quality option of a tumor).
Helps to define the clinical forecast for each patient medulloblastomy the classification offered by Chiang in 1969. It is based on the principles of TNM and considers the new growth size, metastasis and extent of infiltration.
Clinical manifestations of a medulloblastoma can be different. They depend on localization of a new growth, on expressiveness of an all-brain syndrome which is directly connected with increase in intra cranial pressure, and from an arrangement of metastasises.
As the medulloblastoma most often settles down in a cerebellum, at the patient the cerebellar ataxy develops. "cerebellar gait" is formed: the patient goes, having placed the lower extremities and balancing top not to lose balance and not to fall; "throws" it here and there. Owing to an incoordination of movements, the patient often falls, especially at turns. If the tumor sprouts in a brain trunk, the state worsens at once as disorders of breath and haemo dynamics join. In the neurologic status comes to light: oppression of a pharyngeal reflex, look paresis, spontaneous , convergence violation. If the spinal cord is involved, there are paralyzes of extremities, sensitivity violations.
Changes of consciousness in the form of psychomotor excitement, the increased irritability, violations of orientation in the place, time, own personality are characteristic of all-brain manifestations of a medulloblastoma. Quite often at the patient convulsive attacks are noted. The patient shows complaints to a morning headache, constant nausea, repeated vomiting which are components of a syndrome of intrakranialny hypertensia. Timely diagnosing of a medulloblastoma at children of early age is complicated by features of a structure of their skull. The syndrome of intra cranial hypertensia can not be shown long time as the cranium sizes at children are increased, the brain is plastic, and vessels very elastic. Quite often the diagnosis is made late when the medulloblastom is occupied by a worm, to a gemisfer of a cerebellum and the fourth ventricle of a brain; sprouts in bulbarny structures.
Metastasises considerably worsen a condition of the patient. The clinical picture depends on their localization and the sizes. Medulloblastoma — a tumor unusual, unlike primary new growths of a brain (an astrotsitoma, a glioma) which do not give metastasises outside the central nervous system, this tumor is capable to spread in a liver, lungs and bones (approximately in 5% of cases).
The most frequent complication of a medulloblastoma — development of hydrocephaly (brain dropsy). It occurs due to blocking of outflow of a likvor the growing tumor, or in the field of a brain water supply system, or Lyushk and Marangdi's openings. Are characteristic of hydrocephaly: round-the-clock persistent headaches, nausea, frequent zaprokidyvaniye of the head, shift of eyeballs down, and squint; at children - the skull increased in volume.
With diagnostic the purpose the neurologist makes a total score of data of neurologic, ophthalmologic, likvorologichesky researches, and also results of KT or MPT of a brain. For comprehensive examination and delivery of the diagnosis of a medulloblastoma results of the following types of researches can be required: general blood test, general analysis of urine, blood biochemistry; survey of the ophthalmologist which when carrying out an oftalmoskopiya reveals the stagnant disks of optic nerves testifying to intrakranialny hypertensia; a neyrosonografiya at children with open fontanels, providing the earliest diagnosis of a tumor; the computer tomography (CT) which gives the chance to define precisely location and the sizes of a tumor, extent of infiltration of surrounding brain fabric; the magnetic and resonant tomography (MRT) allowing to reveal the most minor changes in structure of a brain; the positron and issue tomography (PIT) estimating process of metastasis; definition of onkomarker in blood; a biopsy (the gistopatologichesky analysis of fabrics) for drawing of the final clinical diagnosis; consultation of the neurosurgeon.
Treatment of a medulloblastoma
Radical method of treatment of a medulloblastoma is its surgical removal. If the condition of the patient allows, it is better total to delete a cancer tumor. During operation microsurgical techniques, intraoperative MRT-navigation are used.
The radiotheraphy takes the important place in therapy of this pathology. If the medulloblastoma is removed completely and there are no metastasises, after surgery the radiotheraphy in low doses is appointed that minimizes side effects. If metastasises are revealed or the new growth is removed not absolutely, the radiotheraphy in high doses is applied. At the impressive sizes of a medulloblastoma radiation therapy is shown before removal of a tumor for the purpose of reduction of its sizes to operable. To children is younger than three years the radiotheraphy is not carried out.
The chemotherapy in treatment of this tumor is a part of complex measures and is used after surgical and radiological therapy. Use of the following chemotherapeutic medicines is the most effective: vinkristina, nitrozomochevina and pro-carboazine.
The American scientists suggested to use a measles virus in complex treatment of a medulloblastoma quite recently, previously having subjected it to genetic modification. Experiences on mice confirmed that the modified virus of measles kills malignant cages of a medulloblastoma in only 72 hours.
The mode and diet — other part of system treatment of a tumor. Is it is necessary in the small portions, but it is frequent. It is not necessary to force the patient to eat food. It is recommended to eat more citrus. At preparation of dishes it is necessary to consider the patient's wishes, his flavoring addictions against the background of treatment can change and even to seem strange. Rehabilitation — an integral part of treatment of a medulloblastoma. It is developed individually for each patient.
Forecast and prevention of a medulloblastoma
Today the lethality and an invalidization at a medulloblastoma remain very high. Are important for decrease in frequency of failures of a tumor: early detection of a disease, completeness of inspection and choice of an optimum method of surgical treatment of a new growth.
The postoperative lethality is equal to 5%, and after five years only 20 - 30% of patients of medulloblastomy survive. Survival at boys makes more than five years about 24%, and girls have only 10%. The age of the sick child, the zlokachestvenny new growth is younger, and the quicker the brain trunk which is responsible for vital functions is involved in pathological process. Patients with a tumor recurrence after its removal have the worst forecast.
Specific methods of prevention of a medulloblastoma do not exist now. There are researches of the American doctors who report that reception of vitamin supplements during pregnancy reduces risk of developing of this tumor.