Extraventricular neurocytoma

Extraventricular neurocytoma (EVN), also known as cerebral neurocytoma or atypical neurocytoma when located outside the ventricular system, is a rare brain tumor classified as a WHO grade II or III neoplasm. Unlike its more common counterpart, central neurocytoma, which arises within the lateral ventricles, extraventricular neurocytoma develops within the brain parenchyma (the substance of the brain itself) outside the ventricular system. It can occur in various locations including the cerebral hemispheres, thalamus, cerebellum, brainstem, and spinal cord. The tumor is composed of small, uniform round cells with neuronal differentiation and shares histological features with central neurocytoma. Symptoms of extraventricular neurocytoma depend on the tumor's location and size. Common presentations include headaches, seizures, focal neurological deficits (such as weakness or sensory changes), visual disturbances, and signs of increased intracranial pressure. Because the tumor can arise in diverse locations within the central nervous system, the clinical presentation is highly variable. Some patients may experience cognitive changes or personality alterations if the tumor involves the frontal or temporal lobes. The primary treatment for extraventricular neurocytoma is surgical resection, with gross total resection being the most important prognostic factor. When complete surgical removal is achieved, outcomes are generally favorable. However, EVN may have a somewhat more aggressive clinical course compared to central neurocytoma, with higher rates of recurrence, particularly in cases with atypical histological features (increased mitotic activity, vascular proliferation, or necrosis). Adjuvant radiation therapy may be considered for incompletely resected tumors, recurrent disease, or tumors with atypical features. The role of chemotherapy remains less well defined and is generally reserved for recurrent or progressive cases. Long-term follow-up with serial neuroimaging is recommended due to the potential for late recurrence.

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

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