Diffuse astrocytoma

Diffuse astrocytoma is a slow-growing (WHO grade II) brain tumor that arises from star-shaped glial cells called astrocytes, which provide support and nourishment to neurons in the central nervous system. Previously classified under the broader category of low-grade gliomas, diffuse astrocytoma is characterized by its infiltrative growth pattern, meaning tumor cells spread diffusely into surrounding brain tissue rather than forming a well-defined mass. Common synonyms include low-grade diffuse astrocytoma and grade II astrocytoma. Under the current WHO classification, molecular markers such as IDH (isocitrate dehydrogenase) mutation status are used to further subclassify these tumors. The tumor primarily affects the cerebral hemispheres of the brain, though it can occur in other locations within the central nervous system including the brainstem and spinal cord. Key symptoms depend on tumor location but commonly include seizures (often the presenting symptom), headaches, cognitive changes, personality or behavioral alterations, and focal neurological deficits such as weakness, speech difficulties, or visual disturbances. Symptoms typically develop gradually due to the slow-growing nature of the tumor. Treatment for diffuse astrocytoma generally involves a combination of approaches. Surgical resection is the primary treatment when feasible, with the goal of removing as much tumor as safely possible while preserving neurological function. Radiation therapy and chemotherapy (commonly temozolomide) may be recommended following surgery, particularly for tumors that cannot be completely resected or that show signs of progression. Despite being classified as a lower-grade tumor, diffuse astrocytomas carry a risk of malignant transformation to higher-grade gliomas (such as anaplastic astrocytoma or glioblastoma) over time, necessitating long-term monitoring with regular MRI imaging. The ICD-10 code D33.2 reflects its classification as a benign neoplasm of the brain, though its infiltrative behavior and potential for progression distinguish it from truly benign tumors. Prognosis varies considerably depending on factors including patient age, tumor location, extent of resection, IDH mutation status, and other molecular features.

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

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