MedGen

Oligoastrocytoma is a type of low-grade glioma with a mixed astrocytoma and oligodendroglioma histology, manifesting with headaches, speech and motor problems, seizures and, in some, subarachnoid haemorrhage. [from ORDO]

A rare variant of diffuse astrocytoma. It is predominantly composed of neoplastic astrocytes showing a small cell body with few, flaccid processes with a low content of glial filaments and scant GFAP expression. This lesion is not well defined and is considered by some authors as an occasional histopathological feature rather than a reproducibly identifiable variant. When occurring in children, this neoplasm may be difficult to separate from pilocytic juvenile astrocytoma. (Adapted from WHO) [from NCI]

Glioblastomas are malignant astrocytic tumors (grade IV according to the WHO classification). [from ORDO]

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]