Protoplasmic astrocytoma

Protoplasmic astrocytoma is a rare subtype of diffuse astrocytoma (WHO grade II), a low-grade brain tumor arising from astrocytes, which are star-shaped glial cells that support neurons in the central nervous system. This tumor is classified under the ICD-10 code C71.9 (malignant neoplasm of brain, unspecified). Protoplasmic astrocytomas are characterized by a low cellularity, mucoid or microcystic degeneration, and tumor cells with few, thin processes. They are among the rarest variants of diffuse astrocytomas and tend to occur in the cerebral cortex and temporal lobes. Because they are brain tumors, they can affect neurological function depending on their location and size. Patients may present with seizures, headaches, cognitive changes, personality alterations, focal neurological deficits, or signs of increased intracranial pressure. Symptoms often develop insidiously over months to years due to the slow-growing nature of the tumor. Diagnosis is typically made through neuroimaging (MRI) and confirmed by histopathological examination of tissue obtained via biopsy or surgical resection. Treatment generally involves maximal safe surgical resection when feasible, which is the primary therapeutic approach. Depending on the extent of resection, patient age, and molecular characteristics of the tumor, adjuvant therapies such as radiation therapy and/or chemotherapy (commonly temozolomide) may be considered. Despite being classified as low-grade, protoplasmic astrocytomas carry a risk of progression to higher-grade gliomas over time. Under the updated WHO 2021 classification of central nervous system tumors, the histological subtyping of diffuse astrocytomas (including the protoplasmic variant) has been largely replaced by molecular classification based on IDH mutation status and other genetic markers. Long-term follow-up with serial imaging is essential for monitoring disease progression.

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