MedGen

Oligodendroglioma is a type of diffusely infiltrating glioma and constitutes approximately 5% of primary intracranial tumors. They often involve the cortical gray matter and are most commonly seen in the frontal lobes. OGs are generally low grade WHO grade II neoplasms that are slow-growing tumors and have a favorable treatment response when compared to other gliomas. Grade III anaplastic OG is a more malignant form of the tumor which portends a less favorable prognosis and may occur de novo or as degeneration from the lower grade OG. [from HPO]

Astrocytoma is a neoplasm of the central nervous system derived from astrocytes. Astrocytes are a type of glial cell, and thus astrocytoma is a subtype of glioma. [from HPO]

An oligodendroglioma occurring during adulthood. [from NCI]

A rare glial tumor characterized by a grade III oligodendroglial tumour with focal or diffuse anaplastic features. It typically occurs in the supratentorial white matter. Histologically, the cells are enlarged and epithelioid with pleomorphic and increased size nuclei, a vesicular chromatin pattern and prominent nucleoli. Most patients present with seizures. [from ORDO]