<unk> s are extremely rare brain tumors that together with oligodendrogliomas account for approximately 10% of primary CNS tumors. They are a subtype of gliomas and account for 25% of all gliomas. These tumors are composed of astrocytoma and oligodendroglioma. Celli et al in 1994 gave the name of<unk> " to those oligodendroglial tumors where the astrocytes formed more than 20% of the tumor cells. Morphologic characteristics of<unk> s resemble those of pure oligodendrogliomas and astrocytomas.<unk> s are primarily tumors of adulthood with peak incidence in 4th to 6th decade of life. Even though these tumors can arise anywhere within the the brain, but usually in the supratentorial region, especially frontal and temporal lobes are the most common sites. Based on WHO classification,<unk> s are devided into two classes:<unk>  corresponding to grade II and anaplastic<unk>  corresponding to grade III. Clinical manifestaions of<unk>  vary and can range from seizure and headaches to personality changes. Many risk fators seem to play a role in pathogenesis of<unk> . The molecular changes can resemble those of oligodendrogliomas (loss of heterozygosity on 1p and 19q, in 30-70% of cases) or astrocytoma (TP53 mutation and loss of heterozygosity on 17p). Treatment is based on sugery, however the tumor is responsive to chemotherapy in most cases, when necessary.
Oligoastrocytoma
Gemistocytic astrocytoma
Hemangiopericytoma
Protoplasmic astrocytoma
Astrocytoma
Subependymal giant cell astrocytoma
Schwannoma
Hemangioblastoma