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Pineoblastoma of the brain
Last reviewed: 18.10.2021
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A blastoma, a rare type of cancerous neuroectodermal tumor, in the pineal or pineal endocrine gland of the brain is defined as brain pineoblastoma.
In the ICD-10 section of neoplasms, this tumor has the code C75.3 (malignant neoplasm of other endocrine glands). According to the WHO classification, pineoblastomas are considered grade IV tumors. [1]
Epidemiology
According to statistics, in the majority of cases, brain pineoblastoma is detected in children from one to 12 years old, which accounts for 1-2% of cerebral malignant neoplasms detected in childhood. But almost half of the pineal gland tumors are pineoblastomas, the latent period of which is five years on average. [2]
Pineoblastoma of the brain in adults is diagnosed in no more than 0.5% of all tumors of brain structures.
Causes pineoblastomas
The pineal (pineal) endocrine gland - the pineal gland (pineal gland ) - is located in the midbrain. It produces melatonin (which synchronizes the sleep-wake cycle), the neurotransmitter serotonin, and the lipid hormone adrenoglomerulotropin (a stimulator of aldesterone synthesis by the adrenal cortex).
The specific causes of pineoblastoma are unknown, although there is evidence that it is linked to certain genetic abnormalities - germline mutations in tumor suppressor genes RB1 or DICER1.
Experts do not exclude that such risk factors as exposure to the fetus of an increased level of radiation in the environment, intrauterine intoxication or oxygen starvation of the fetus during ontogenesis can lead to negative changes at the level of sporadic gene mutations in cells of the forming structures of the brain.
However, the most likely factor that increases the likelihood of developing pineoblastoma is a hereditary predisposition if the parents have changes in the gene that are transmitted to the child in an autosomal dominant manner. [3]
Pathogenesis
The mechanism of the multistep process of oncogenesis in the development of brain pineoblastoma remains the subject of research.
The adult pineal gland consists of pinealocytes, astrocytes, microglia, and other interstitial cells. Its formation during embryogenesis goes through three stages with the beginning in the form of a neuroepithelium process in the roof of the third ventricle of the brain. The primordium is formed by progenitor cells (multipotent stem cells) Pax6; pinealocytes of the pineal parenchyma are also formed from progenitor cells. These are intermediate, partially differentiated cells called blastocytes.
The pathogenesis of pineal blastoma is seen in the fact that at one of the stages of pineal gland formation, due to mutations in tumor suppressor genes that regulate cell growth and expression of DNA proteins, uncontrolled mitosis of blastocytes occurs. [4]
Symptoms pineoblastomas
The early or first signs of brain pineoblastoma are manifested in the form of headache, nausea and vomiting. This is a consequence of an increase in intracranial pressure due to the accumulation of cerebrospinal fluid around the brain - hydrocephalus. [5]
Other symptoms depend on the size of the tumor and its spread to adjacent parts of the brain, including:
- increased fatigue;
- instability of body temperature;
- visual disturbances (changes in eye movements in the form of nystagmus, double vision, strabismus);
- decreased muscle tone;
- problems with coordination of movements;
- sleep disorders;
- memory impairment.
Complications and consequences
Although pineoblastoma of the brain goes beyond its limits very rarely, in addition to the spread of metastases of this malignant neoplasm through the cerebrospinal fluid, the consequences and complications are relapses and the development of neurological, cognitive and endocrine disorders of varying degrees.
In particular, there is a dysfunction of the pituitary gland, which leads to growth retardation and sexual development.
Diagnostics pineoblastomas
If a pineoblastoma is suspected, the diagnosis cannot be based on the clinical picture: blood tests for neuron-specific enolase and chromogranin-A are required; also needs analysis of cerebrospinal fluid, which is taken using a lumbar puncture .
Biopsy for histological examination of tumor cells can be done by aspiration before the operation to remove the pineoblastoma or directly during it.
Instrumental diagnostics is of decisive importance: MRI or CT of the brain, magnetic resonance spectroscopy, PET (positron emission tomography).
Differential diagnosis
Differential diagnosis is carried out with pineal cyst, teratoma , glioma (glioblastoma multiforme), germinoma, embryonic carcinoma, medulloblastoma , papillary tumor, pineocytoma.
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Treatment pineoblastomas
Pineoblastoma is very difficult to treat, and its basis is surgical treatment - removal of as much of the tumor as possible.
After the operation, adults and children over three years of age receive radiation therapy for the entire brain and spinal cord - craniospinal radiation, as well as chemotherapy. And children under three years of age after removal of the tumor can only receive chemotherapy. [6]
Prevention
The development of this swelling is currently impossible to prevent.
Forecast
Pineoblastoma of the brain - the most aggressive tumor of the pineal parenchyma - has a poor prognosis, which is due to their rapid growth and spread to other cerebral structures.
The overall five-year survival rate for children with pineoblastoma is 60-65%, for adults - 54-58%.