Symptoms of Meningioma
Meningiomas are typically benign and slow-growing tumors of the meninges, which is a protective layer around the brain and spinal cord. Despite the slow-growing nature of these tumors, compression of vital brain tissue can cause a variety of symptoms and neurological deficits. Certain areas of the brain are more resilient to compression than others and can adapt as the tumor grows slowly. This allows some meningiomas to grow quite large without causing major symptoms.
In contrast, small meningiomas located in more sensitive areas and producing edema (brain swelling) may cause many symptoms. In this article, we will discuss the types of meningiomas and how symptoms develop based on the location from which they arise.
Types of Meningiomas
Meningiomas have a variety of subtypes. In fact, 15 histological subtypes are recognized by the World Health Organization (WHO), which can be further divided into three distinct groups:
- WHO Grade I (Benign): Nine of the 15 subtypes are benign and are the ones most commonly encountered by neurosurgeons:
- Fibrous (fibroblastic)
- Transitional (mixed)
- WHO Grade II (Atypical): Three of 15 subtypes contain mixed features of benign and malignant tumors:
- Clear Cell
- WHO Grade III (Malignant): Three of 15 subgroups are malignant:
Histological comparisons play a role in prognostication and lifespan but can only be identified with a tissue sample obtained during surgery to remove the tumor. On a practical level, meningiomas can also be grouped by the anatomic location from which they arise. For example, it is very common for neurosurgeons to diagnose and treat clival, convexity, foramen magnum, olfactory groove, posterior fossa, and suprasellar meningiomas. Each anatomic location and the associated tumor has a distinct set of symptoms and requires unique surgical corridors to remove the tumor.
Symptoms of Meningiomas Vary by Location
Meningiomas most often cause symptoms by pressing on nearby structures. Given that different parts of the brain and spinal cord are responsible for different functions, meningiomas can cause a variety of symptoms depending on their location.
For example, a meningioma compressing the part of the brain that is responsible for producing speech, called Broca’s area, may result in a loss of fluency and cadence in verbal speech. Moreover, a meningioma compressing parts of the frontal lobe, which is the part of the brain that contributes to our individual personality, may cause a patient to have a personality change, become aggressive, or exhibit a lack of inhibition.
Here, we will discuss some of these common locations of meningiomas and describe the symptoms they may produce:
- Intraventricular meningioma: Intraventricular meningiomas are found within the ventricles, which are chambers located deep within the brain that hold cerebrospinal fluid (CSF). CSF is a clear fluid that bathes the brain and spinal cord and is constantly produced and reabsorbed. If the natural flow of CSF is obstructed by these tumors, the ventricles can swell in a condition called hydrocephalus. Hydrocephalus is characterized by increased pressure in the brain leading to headaches, nausea and vomiting, lethargy, as well as visual and cognitive changes.
- Parasagittal meningioma: Parasagittal meningiomas most commonly develop near the surface along the midline of the brain, or slightly to one side. Compression of midline brain structures can cause headaches, seizures, personality changes, and weakness of the lower extremities.
- Falcine meningioma: Falcine meningiomas develop on the falx cerebri, which is the part of the meninges that separates the two hemispheres (left and right sides) of the brain. Depending on whether the tumor is more rostral (towards the nose) or caudal (towards the back of the head), falcine meningiomas can cause personality changes, motor deficits, such as muscle weakness, and/or visual disturbances.
- Clival meningioma: Clival meningiomas occur at the base of the brain in the posterior fossa, which is the back part of the skull. These tumors can have a wide variety of effects depending on where they originate and what part of the brain they compress in this region. Symptoms may include problems with coordination, swallowing, walking, hearing, and nausea. They can also cause blurry vision and headaches.
- Convexity meningioma: Convexity meningiomas develop on the curved surface of the brain and can cause many symptoms. For example, tumors near the pre-central gyrus (also known as the motor-strip) can cause weakness or paralysis of the hand, face, or arm on the opposite side of the tumor. Additionally, if a tumor develops near the occipital lobe (back of the brain), patients may experience visual disturbances.
- Foramen magnum meningioma: The foramen magnum is the large hole at the bottom of the skull through which the brain becomes the spinal cord and exits the skull. Foramen magnum meningiomas can cause compression quite easily. This small space also contains many very sensitive brain structures and is therefore susceptible to injury. Symptoms of these tumors may include worsening of balance, loss of muscle tone in various parts of the body, pain in the upper neck or back of the head, sensory changes, and dysfunction of several cranial nerves.
- Olfactory groove meningioma: Olfactory groove meningiomas, found near the nerves that are responsible for the sense of smell, can result in changes or loss of a patient’s ability to smell. These tumors typically reach a giant size and lead to personality changes due to compressing the frontal lobes.
- Cerebellar (posterior fossa) meningioma: The cerebellum is responsible for balance and coordination of movements. Cerebellar meningiomas cause changes in balance and lack of coordination of movements.
- Suprasellar meningioma: Suprasellar meningiomas often cause issues with the pituitary gland, and therefore lead to changes in hormones. They can also result in headaches, seizures, and vision changes (due to their vicinity to the eye nerves).
Meningiomas are typically benign, slow-growing tumors that affect the protective covering of the brain, called the meninges. Because the meninges cover the entire surface of the brain, a variety of symptoms may occur. Fortunately, neurosurgeons are trained to correlate the history of your symptoms, physical examination findings, and diagnostic imaging to determine the next course of action.
- Meningiomas are most often slow-growing benign tumors that can compress structures in the brain and spinal cord and lead to a variety of symptoms.
- They form from the meninges, or protective coverings surrounding the brain.
- The symptoms that develop depend on the part of the brain that is being compressed.