Oligoastrocytoma is a term used to describe a rare type of brain tumor that arises from two kinds of brain cells, the oligodendrocytes and astrocytes. This type of tumor is considered more difficult to treat because it combines features of both oligodendroglioma and astrocytoma. There are several synonyms for oligoastrocytoma, including mixed glioma, mixed glioblastoma, and anaplastic oligoastrocytoma. These terms are used interchangeably in medical literature to describe tumors that exhibit mixed characteristics of both these cell types. Oligoastrocytoma is graded on a scale of 1-4, with grade 4 being the most severe and becoming known as glioblastoma. Treatment options vary depending on the severity of the tumor and can include surgery, radiation therapy, and chemotherapy.