Oligoastrocytoma

Oligoastrocytoma, also known as mixed oligoastrocytoma or mixed glioma, is a rare brain tumor that historically was classified as containing both oligodendroglial and astrocytic tumor cell components. It falls under the broader category of diffuse gliomas and is classified under ICD-10 code C71.9 (malignant neoplasm of brain, unspecified). These tumors primarily affect the central nervous system, most commonly arising in the cerebral hemispheres, particularly the frontal and temporal lobes. Oligoastrocytomas were traditionally graded as either WHO grade II (low-grade) or WHO grade III (anaplastic oligoastrocytoma), with the anaplastic variant carrying a worse prognosis. Key symptoms depend on tumor location and size but commonly include seizures, headaches, cognitive changes, personality or behavioral alterations, focal neurological deficits such as weakness or speech difficulties, and increased intracranial pressure. Seizures are frequently the presenting symptom, particularly in lower-grade tumors. Some patients may experience nausea, vomiting, or visual disturbances as the tumor grows and exerts mass effect on surrounding brain structures. It is important to note that the 2016 and 2021 WHO Classifications of Tumors of the Central Nervous System have largely eliminated oligoastrocytoma as a distinct diagnostic entity. Advances in molecular diagnostics, particularly IDH mutation status and 1p/19q codeletion testing, now allow most previously diagnosed oligoastrocytomas to be reclassified as either oligodendrogliomas (IDH-mutant, 1p/19q-codeleted) or astrocytomas (IDH-mutant, non-codeleted). Treatment typically involves a combination of maximal safe surgical resection, radiation therapy, and chemotherapy (often with temozolomide or PCV regimen consisting of procarbazine, lomustine, and vincristine). Prognosis varies based on molecular profile, tumor grade, extent of resection, and patient age.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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