A meningioma is a type of brain tumor that originates in the meninges, the protective layers of tissue surrounding the brain and spinal cord. These tumors are generally slow-growing and non-cancerous, or benign. While often not malignant, their presence and growth can still pose significant health concerns depending on their size and location within the confined space of the skull.
Understanding Meningiomas
Meningiomas are the most common type of primary brain tumor, forming in the three layers of membranes known as the meninges that encase the brain and spinal cord. They are frequently found near the top and outer curve of the brain or at the base of the skull. These tumors are typically slow-growing and often exist for years without noticeable symptoms. Most are classified as Grade I by the World Health Organization (WHO), indicating their benign nature. Despite being non-cancerous, their expansion can exert pressure on nearby brain tissue, nerves, or blood vessels, leading to various neurological issues.
Consequences of Untreated Meningioma
When a meningioma is left untreated and continues to grow, it can lead to worsening symptoms or new neurological deficits. Growing tumors can press on the brain, causing increased intracranial pressure, manifesting as persistent headaches, often worse in the morning.
Pressure on specific brain regions or nerves can lead to a range of sensory and motor impairments. A tumor near the optic nerve can cause vision changes, such as blurring, double vision, or even vision loss. If the tumor affects areas controlling movement, individuals may experience weakness or numbness in their arms or legs, or difficulties with balance and coordination. Tumors in certain locations might also trigger seizures, which can be generalized, affecting both sides of the brain, or partial, impacting specific body parts.
Cognitive functions can also be compromised as the tumor expands. This might include memory loss, trouble focusing, or language and speech difficulties. Personality changes or altered mental status, including reversible dementia, can occur, particularly with tumors in the frontal regions or olfactory groove. Tumors in the posterior fossa, at the back of the head, can lead to unsteadiness, dizziness, changes in voice, or swallowing difficulties due to the limited space in that area.
When Observation is a Medical Option
Leaving a meningioma “untreated” does not always signify neglect; it can be a carefully considered medical approach known as “watchful waiting” or “observation.” This strategy is often recommended for small meningiomas that are not causing any symptoms. It is also a common choice for elderly patients or individuals with other significant health issues where the risks associated with surgery or other treatments might outweigh the benefits.
Observation involves regular monitoring of the tumor’s size and the patient’s symptoms through periodic magnetic resonance imaging (MRI) scans, typically every 3 to 12 months initially. The frequency of these scans may be adjusted if the tumor remains stable. The goal is to track the tumor’s growth rate and identify any new or worsening symptoms that would then prompt a re-evaluation of the treatment plan. Intervention, such as surgery or radiation, becomes necessary if the tumor shows significant growth, if new symptoms emerge, or if existing symptoms become more severe or debilitating.
Long-Term Outlook
The long-term outlook for individuals with meningiomas that are not actively treated varies widely, depending on factors such as tumor grade, size, location, and the patient’s overall health. While many benign, slow-growing meningiomas may remain stable for years under observation, others will eventually progress. If growth continues unchecked, the increasing pressure on brain structures can lead to progressive disability and a significant decline in quality of life.
Unmanaged symptoms like severe headaches, vision loss, or seizures can profoundly impact daily activities, independence, and overall well-being. Although meningiomas are often benign, even Grade I tumors can lead to long-term neurological problems for a majority of patients, and can be associated with an increased risk of stroke. While the five-year survival rate for non-cancerous meningiomas is generally high, ranging from 87% to over 95% depending on age, the potential for complications and decreased quality of life without intervention remains a serious consideration.