Meningioma
Overview
Plain-Language Overview
Meningioma is a type of tumor that grows from the protective layers covering the brain and spinal cord, called the meninges. It primarily affects the central nervous system by pressing on nearby brain tissue or nerves. These tumors are usually slow-growing and often benign, meaning they are not cancerous. Symptoms can vary widely depending on the tumor's size and location, including headaches, vision changes, or weakness. Diagnosis often involves imaging tests like MRI scans to visualize the tumor. Treatment options depend on symptoms and tumor characteristics but may include surgery or radiation. Understanding this condition helps explain how abnormal growths in the brain's protective layers can impact overall brain function.
Clinical Definition
Meningioma is a typically benign, slow-growing neoplasm arising from the arachnoid cap cells of the meninges, the membranous layers surrounding the brain and spinal cord. It represents the most common primary intracranial tumor in adults and is often linked to chromosomal abnormalities such as loss of chromosome 22q, which includes the NF2 gene. These tumors can cause neurological symptoms by exerting mass effect on adjacent brain structures or cranial nerves. Histologically, meningiomas are characterized by whorled cell patterns and psammoma bodies. Although most are benign (WHO grade I), atypical (grade II) and anaplastic (grade III) variants exist with more aggressive behavior. The clinical significance lies in their potential to cause focal neurological deficits, seizures, or increased intracranial pressure depending on size and location.