Anaplastic astrocytoma

Anaplastic astrocytoma as a malignant brain tumor is called, which is characterized by diffuse growth, increased cell density and mitotic figures. It originates from a particular population of cells of the central nervous system, astrocytes. The tumor corresponds according to the WHO classification of tumors of the central nervous system a grade III tumor.

Epidemiology and clinical

Anaplastic astrocytomas typically occur in the medulla ( white matter ) of the brain in adults. The average age at diagnosis is 45 years. The male to female ratio is 1.6 to 1 The tumors can arise de novo or through a progression from a diffuse astrocytoma WHO grade II. The tumor infiltrated diffusely without it completely destroying the surrounded brain tissue, so that the affected brain structures impress enlarged. The tumor shows in imaging usually a focal contrast enhancement.

Neuropathology

The biopsy samples of the tumor typically show a raised density and cell nuclear division figures. The proliferative activity of the tumor is usually about 5%. With immunohistochemical methods, the astrocytic origin of the tumor are secured by detection of GFAP. In more than half of the mutations of the TP53 tumor protein and isocitrate dehydrogenase can be detected in the tumor.

Therapy

The current standard treatment consists of surgical removal of the tumor ( resection) as far as possible, followed by radiation therapy and chemotherapy.

Forecast

The prognosis is poor, the tumor usually shows within two years, a progression to glioblastoma. Anaplastic tumors without evidence of IDH mutation show a poorer outcome than glioblastomas with such a mutation.