Diagnosis of brain astrocytoma

The problem of timely diagnosis and effective treatment of brain tumors is complicated by the late treatment of patients for help. How many rush to the doctor with a headache, especially if the symptom appeared not so long ago? And when vomiting joins pains in the head, the tumor often already has time to increase markedly, especially if it is a malignant neoplasm. If the tumor is small, there may be no permanent symptoms at all.

In the early stages, a brain disease can be detected by chance during a tomogram or x-ray examination. But for such a survey also requires good reasons.

Regardless of whether the patient came to the reception with complaints or a tumor was detected during the examination, the doctor will be interested in the symptoms. The neurological status is first assessed. We are talking about the presence of symptoms such as headaches, nausea, vomiting, dizziness, and convulsive seizures. The doctor also studies the presence of cerebral symptoms such as fatigue, cognitive decline, as well as local symptoms that may vary depending on the location of the tumor, and a preliminary assessment of the degree of intracranial hypertension (fundus fundus study).

Clinical examination

During the physical examination, an assessment of the general somatic status is carried out according to the Karnovsky or ECOG scale [1]. This is an assessment of a person’s ability to lead a normal, active life, to serve himself without help, the need for medical care, which is also used in the management of cancer patients. According to Karnovsky, the indicator 0-10 indicates that a person dies or is already dead, with 20-40 points a person must be hospitalized, 50-70 points indicate not the patient’s disability and the need for medical care, 80-100 indicate normal activity with varying severity symptoms of the disease.

If the patient is taken to a medical facility in a serious condition, consciousness is assessed on the Glasgow scale. Three main features are assessed: eye opening, speech activity, motor reaction. The result is determined by the sum of points. The maximum number of points (15) indicates a clear mind, 4-8 points - indicators corresponding to coma, and 3 points indicate the death of the cerebral cortex.

Analyzes

Habitual tests, assigned rather to assess the general condition of the patient and the presence of concomitant diseases, are not indicative of tumors. The present changes in clinical and biochemical analysis of blood are not specific, but they will be a guideline in the appointment of treatment. Additionally, such studies can be prescribed (urinalysis, HIV antibody test, Wasserman reaction, determination of hepatitis B and C markers, tumor antigen). Since the treatment of tumors is usually associated with surgery, which may require a blood transfusion, a blood group and Rh test are considered mandatory. Molecular diagnosis of gliomas is increasingly being used in routine clinical practice [2], [3], [4]. Also launched a pilot project of early screening of astrocytomas of the brain using mrt scan [5].

Histological examination of a sample of a tumor taken during a biopsy is considered mandatory. But the problem is that it is not possible to take such a sample without an operation. Most often, small areas of the tumor are examined after its removal. Although modern medicine does not today have at its disposal new methods of minimally invasive biopsy (for example, stereotactic biopsy, carried out in two ways), which are applied on the basis of the results of instrumental studies.[6]

Instrumental diagnostics

Instrumental diagnosis of brain tumors includes:

• Magnetic resonance (MRI) or computer (CT) examination of the brain. Preference is given to MRI, which is carried out in 3 projections and 3 modes without the use of contrast and with it. If MRI is not possible, a CT scan is performed, including contrast.  [7]
• Additional MRI features:
  • Diffusion MRI, which determines the quantitative indicators of the diffusion of water molecules in the brain tissues¸, making it possible to assess the blood supply to the tissues of the organ, the presence of brain edema, and degenerative processes in it.
  • Mo-perfusion of the brain, allowing to evaluate the characteristics of the blood circulation of the brain and differentiate various pathologies. [8]
  • MRI spectroscopy, which helps to assess metabolic processes in the brain and determines the exact boundaries of the tumor.
• Additional studies:
  • Positron emission tomography (PET) is an innovative method that makes it possible to detect a tumor almost in the bud itself. It can detect tumors of the smallest size. It is also used for the differential diagnosis of recurrent glial tumors.[9], [10]
  • Direct or CT angiography is a study of cerebral vessels, which is prescribed if preliminary studies have revealed an abundant blood supply to the tumor. Angiography also allows you to determine the degree of damage to the blood vessels of the brain.
• X-ray. This is not the most reliable method for diagnosing tumor processes; nevertheless, an x-ray of the spine can be a starting point for subsequent CT scans and MRI, if the doctor sees a suspicious area in the picture.

Electrocardiogram, electroencephalogram, ultrasound, radiography of organs, broncho-and gastroduodenoscopy (in the presence of concomitant diseases), i.e. We are talking about a complete comprehensive examination of the patient, which influences the choice of a tumor treatment protocol.

It is recommended to conduct an instrumental study not only at the stage of diagnosing the disease, but also in the postoperative period to assess the quality of the operation and predict possible complications. In the case of diffuse tumors that do not have a clear localization, as well as in deep tumors, the doctor actually acts by touch. Subsequent computed tomography, which is the standard for postoperative diagnosis, and recommended MRI with contrast and without contrast should be performed within the first 3 days after surgery.

Differential diagnosis of astrocytomas

The primary diagnosis of astrocytoma of the brain is complicated by the fact that the main symptoms of the pathology are also present in tumors of a different etiology, some organic diseases of the brain, and even somatic diseases. Only through full and thorough differential diagnosis is it possible to establish the exact cause of the symptoms.[11]

A benign nodal astrocytoma on an MRI is often a homogeneous formation with clear boundaries (heterogeneity can be explained by the presence of calcifications and small cysts). When contrasting, such tumors amplify in 40% (this is more characteristic of benign hemstocytic astrocytomas), while in the anaplastic form of astrocytoma, gain is always obvious.

The diffuse astrocytomas in the image look like fuzzy spots with no clearly visible borders. In malignant degeneration of such tumors their structure changes, characteristic heterogeneity appears.

What distinguishes pilocytic astrocytoma and its other nodular varieties from glioblastoma and anaplastic astrocytoma can be identified by the following features: the presence in the first case of clear tumor boundaries and contours, relatively slow tumor growth, the absence of cellular polymorphism, granules, less tumor mass, more or less uniform staining of the pathological focus on MRI. [12]

The main difference between diffuse astrocytomas from local tumors (nodular, focal) consists in the absence of clear boundaries of the neoplasm. The comparative homogeneity of the internal structures of the tumor, the absence of foci of necrosis indicates a low degree of malignancy of the tumor.

Anaplastic astrocytoma is a cross between low-grade diffuse astrocytomas and aggressive glioblastomas. It differs from ordinary diffuse astrocytes in cellular polymorphism (the presence of cells of various shapes, sizes and sizes in the tumor) and mitotic activity, i.e. The number of cells undergoing mitosis. Mitosis is a four-step process of dividing all the cells of the body with the exception of the sex. [13]

Anaplastic astrocytoma is distinguished from glioblastoma by two factors: the absence of necrotic foci and signs of vascular proliferation. Only glial cells divide. The danger of this tumor in its rapid growth and the difficulty of determining the boundaries of localization. Glioblastoma not only grows extremely rapidly (over several weeks and months), but also causes brain cell death, changes in the vessels of the head, completely disrupts the functioning of the organ, which leads to the death of the patient even in the case of treatment.

Great hopes in terms of differential diagnosis are placed on MRI of the brain [14]. This takes into account many factors:

• frequency (glial tumors are detected in 1/3 of patients, almost half of them are astrocytomas of various localization),
• patient's age (astrocytomas of low malignancy are more often diagnosed in children, less often an anaplastic tumor variant, in adults and the elderly, on the contrary, apaplastic astrocytoma and glioblastoma are more common, with a high probability of degeneration into cancer),
• tumor localization (in children, the cerebellum and brain stem structures are more often affected, less often the tumor develops in the area of the optic nerve and chiasm, in adults, tumors are usually formed in the medulla of the cerebral hemispheres and the cortex),
• type of distribution (for glioblastomas and poorly differentiated astrocytomas, the spread of the process to the second hemisphere is considered characteristic).
• the number of foci (multiplicity of foci is characteristic of malignant tumors with metastases, sometimes glioblastoma manifests itself in this way),
• internal structure of the tumor:
  • 20% of astrocytomas are characterized by the presence of calcifications in the tumor, while oligodendroglium tumors contain calcifications in almost 90% of cases (better determined by computed tomography)
  • for glioblastomas and tumors with metastases, characteristic heterogeneity of the structure detected by MRI.
• response to contrast (benign astrocytomas do not tend to accumulate contrast in contrast to malignant),
• diffusion MRI allows differentiation of the tumor process in the brain from abscess, epidermoid cyst, stroke according to the signal strength (it is weaker with tumors) [15]. When stroke is observed characteristic wedge-shaped spots.

Biopsy helps to differentiate the infectious process in the brain from the neoplastic (tumor), to determine the type of tumor cells. If it is impossible to conduct an open operation or deep location of the tumor, a minimally invasive stereotactic biopsy is used, which helps, without opening the skull, to say how dangerous the tumor is in terms of malignancy.