Astrocytoma Atypical

Atypical astrocytoma (a. atypicum; synonym: a. anaplastic, a. heterotypic, a. dedifferentiated, a. malignant, a. malignant) is a glial tumor of the brain, classified as astrocytic tumors of grade III malignancy according to the WHO classification.

It is characterized by the presence of irregularly shaped cells with significant variation in the size and shape of the nuclei. Tumor cells demonstrate an increased number of mitoses, including atypical ones. There is pronounced proliferation of blood vessels. Atypical astrocytoma can arise as a primary tumor or as a result of malignant transformation of benign astrocytomas of lower grades.

Clinically manifested by general cerebral symptoms, convulsive syndrome, focal neurological disorders. It is an aggressive tumor with a poor prognosis. Combined treatment - surgical removal in combination with radiation and chemotherapy.

Astrocytomas are tumors of brain glial cells - neuroglia. They make up the majority of CNS tumors in adults. The most common congenital brain tumor is teratoma. Malignant anaplasia tumor can manifest as primary malignant anaplastic astrocytoma and metastatic malignant anaplastic astrocytic tumor. Differential diagnosis between benign and malignant astrocytomas is based on characteristic clinical and morphological features. A biopsy of tumor tissue reveals the presence of mitoses, neurofibrotic predisposition, and the degree of myxoid/star-shaped cell structure. Atypical astrocytoma usually has a stellate appearance, one nucleolar pigment epithelium, or in the case of anisograde, that is, a complete lack of differentiation from the upper layers along the epithelial bottom, it is atypical. Atypia is signs of immaturity of an atypical neoplasm, characterized by the loss of its cellular structures and the presence of severe defects in their differentiation. These include various combinations of intrapapillary voids, cellular atypia, nuclear deformation, nuclear hyperchromicity, focal loss of cytoplasmic heterogeneity in color and density. In the cell population, mitosis appears with an unequal number and area of ​​bipolar chromatids, as well as a decrease in the area of ​​one of the poles, the nucleus and cytoplasm of mesenchymal cells without clear contours. It is classified as a malignant neoplasm with a high probability of aggressive growth, but in the absence of an invasive process or metastasis to other organs it is called an atypically benign form. Most often, such a complex substance appears as a result of malignancy of typical astrocytomas with low molecular weight