- A primary, slow growing, noninvasive neoplasm of the brain. In children, astrocytomas of the cerebellum represent relatively common benign brain neoplasms. In adults meningiomas, neurilemomas and pituitary tumors comprise the majority of benign tumors.
- Abnormal growth of cells in the nervous system without evidence of malignant characteristics. Unlike other organ systems, tumors in the central nervous system can have benign histological characteristics but still have life threatening effects due to their location within the neuraxis (e.g., brainstem gliomas).