Numerous cells comprise the brain, including neurons, which make up the brain’s electrical circuitry, as well as astrocytes that support and structure neurons to function effectively. Adults are more likely to develop astrocytomas than any other type of brain tumor. These tumors are the most common kind of brain tumor because they arise from astrocytes.
Before the discovery of gemistocyte differentiation in astrocytic tumors, these tumors were thought to be a distinct subtype of the diffuse astrocytic tumor with a substantial gemistocyte component. In either scenario, the prognosis for these tumors is worse than that of other WHO-grade tumors that are matched, and there are no distinguishing imaging findings associated with them.
This is an uncommon kind of diffuse astrocytoma. It is marked by the presence of a large number of gemistocytic neoplastic astrocytes, though the number can vary. Gemistocytes are rounded to oval astrocytes with a large amount of glassy, non-fibrillary cytoplasm that seems to push the nucleus’s black, angulated location to the cell’s edge. A gemistocytic astrocytoma must include more gemistocytes than around 20% of the total tumor cells to be diagnosed.
Gemistocytic Astrocytoma Grading
WHO evaluates astrocytomas based on their growth rate and the likelihood of spreading to neighboring brain tissue. These tumors are divided into four grades by WHO. Most of the time, astrocytomas that do not spread into other parts of the brain grow slower than those that do. Non-infiltrating astrocytomas are less prevalent than infiltrating astrocytomas.
Adult patients’ cerebral hemispheres are the most commonly affected, and men are more likely than women to suffer from this condition. In youngsters, they can manifest in either the cerebral hemispheres or the brain stem. Both are common locations.
Oligodendrogliomas, which originate from oligodendrocytes and are also classified as infiltrating gliomas, are sometimes difficult to differentiate from astrocytomas due to their similar appearance. A subset of infiltrating gliomas are mixed oligodendrogliomas and astrocytomas.
Gemistocytic Astrocytoma Grade 2
Diffused astrocytoma (WHO grade II) is a modestly hypercellular infiltrative tumor composed of well-differentiated astrocytes with low nuclear adenoma. The nuclei are distinctively uneven, angulated, and hyperchromatic. Mitotic figures are nonexistent or infrequent, and neither vascular growth nor necrosis is seen. Gemistocytic astrocytomas are characterized by a predominating population of large, rounded, neoplastic astrocytes. These cells have a huge quantity of glassy, granulomatous cytoplasm that is highly GFAP positive. Additionally, the nucleus of these cells is located in an eccentrically positioned manner.
Low-grade or diffuse astrocytomas, commonly known as grade II astrocytomas, are typically infiltrating tumors. This tumor grows rather slowly and typically lacks distinct borders. People in their twenties to forty years of age are particularly susceptible.
Gemistocytic Astrocytoma Grade 3
Anaplastic astrocytoma is a hypercellular glioma that is classified as WHO grade III. It is made up of moderately differentiated astrocytes and consists of a combination of gemistocytic cells and pleomorphic fibrillary. These cells also have considerable nuclear atypia and high mitotic activity. These cancerous tumors can grow from a low-grade diffuse astrocytoma that was already there or they can start from scratch.
Anaplastic astrocytomas have a median age of roughly 41 years, which lies in between the median ages of individuals with low-grade diffuse astrocytomas and glioblastomas, respectively. After an average of two years, patients with anaplastic astrocytomas often exhibit signs of anaplastic development to glioblastoma.
Grade III astrocytoma is often referred to as anaplastic (cancerous) astrocytoma since this tumor grows faster than grade II astrocytoma. Anaplastic astrocytomas, which make up 4 percent of total brain tumors, most frequently affect individuals between the age of 30 and 50.
Gemistocytic Astrocytoma Grade 4
Although GBM (glioblastoma multiforme) is the most frequent and most aggressive primary brain tumor in adults, it is a sad fact that it is also one of the most common gliomas. GBMs most usually form as solitary tumors in one or both hemispheres of the brain, although they can also occur in the cerebellum or the spinal cord. In many cases, they infiltrate or develop directly within the corpus callosum, with bilateral expansion.
GBM, also known as grade IV astrocytoma, is the most malignant form of nervous system tumor. Due to its many different microscopic manifestations, it is also known as glioblastoma multiforme. Rarely, glioblastomas might have non-glial tissue components. Mixed glioblastoma-sarcoma, or gliosarcoma, is the most prevalent type of GBM displaying these extra tissue features. GBM accounts for 23 percent of all brain cancer, and its most common occurrence is in individuals within the range of the ages 50 and 80. Additionally, the disease is more prevalent in men.