CONVEXITY MENINGIOMAS

Convexity meningiomas are among the most common meningiomas, forming on the outer surface of the brain where the meninges cover the cerebral hemispheres. Because they develop in different regions along the brain’s surface, they are classified according to location. The most frequently recognized types include:

• Frontal meningiomas, which arise in the front portion of the brain;
• Parietal meningiomas, found near the top and sides;
• Temporal meningiomas, affecting the area around the temples; and
• Occipital meningiomas, located at the back of the brain. Each type may cause different symptoms depending on the specific brain functions controlled by the affected region.

Convexity Meningioma Definition/Overview

Convexity meningiomas are superficial tumors arising from the meninges covering the surface of the brain. These tumors are primarily located outside the brain. As the tumor grows, it can press on the underlying brain and cause brain swelling or edema, neurological symptoms, and disability. Occasionally, a tumor invades the overlying cranial bone, and a lump can be felt under the scalp. Doctors classify convexity meningiomas based on their topographic location and relationship to the underlying brain. For example, a frontal meningioma, a parietal meningioma, an occipital meningioma, or a temporal meningioma.

Presentation

In particular, the location of the tumor determines the possible symptoms and deficits associated with it. -Headache – New onset of headache, which can be localized to the location of the tumor or generalized when related to increased intracranial pressure. -Seizure -. Typically, convexity meningiomas in all locations can cause generalized seizures and focal or partial seizures. Therefore, the type of partial seizure is related to the part of the brain affected by the tumor.

Other types of symptoms include:

• A seizure can be the first presentation of meningiomas before diagnosis.
• Vision difficulties – Blurriness or loss of peripheral vision
• Balance/gait difficulties
• Arm and and / or leg weakness (contralateral to the side of the tumor)
• Loss of sensation ( contralateral to the side of the tumor)
• Speech difficulties
• Cognitive changes -Behavioral changes
• Memory loss

Management of Convexity Meningioma

Convexity meningiomas causing symptoms, either related to the affected underlying brain parenchyma or to increased intracranial pressure, are generally treated with surgery. On the other hand, doctors often manage small to medium-sized incidental tumors without brain edema through observation and surveillance MRIs. In addition, elderly patients with small to medium-sized tumors associated with mild symptoms and without significant mass effect can be treated primarily with CyberKnife or Proton Beam radiation therapy.

Surgical Difficulties

• Localization of the tumor
• Close relation to swelled brain
• Tumor size
• Close relation to eloquent brain areas
• Close relation to brain feeding arteries

SURGICAL MANAGEMENT AT THE MENINGIOMA CENTER

Convexity meningiomas are superficial and easily accessible by surgery. In the Center for Meningioma Surgery, surgeons treat these tumors with the smallest possible incision and skull opening (craniotomy), tailored to the tumor’s size and location. The size of the craniotomy and localization of the tumor are guided by a computer-assisted device, which can pinpoint the site and anatomy of the tumor (Stealth Station or BrainLab Station). Tumor resection is carried out with magnification with the surgical microscope to allow elevation of the tumor away from the underlying brain following natural anatomical planes of dissection. This strategy avoids unnecessary trauma or damage to the brain tissue.

Thus, the tumor is removed and dissected in a piecemeal fashion after breaking the tumor with an ultrasonic device, which decreases the tumor pressure and facilitates its dissection. Then, resection of the meningeal origin of the tumor is necessary to allow complete removal of the tumor. When there is an invasion of the overlying cranial bone, doctors remove the involved bone and repair the cranial defect with a cranioplasty. After tumor removal, they repair the meningeal defect, replace the bone flap in its original position, and secure it with small titanium plates and screws. They close the scalp in layers with staples to the more superficial layer.

Prognosis

Finally, treatment of convexity meningioma in all locations through focused small craniotomies and microsurgical technique improves chances of maximal tumor removal. While, preserving function or recovery of function, including pre-operative motor deficits, visual difficulties, speech difficulties, and cognitive dysfunction. Pre-operative seizures are often well controlled with or without medication after atraumatic tumor resection. Small surgical openings or craniotomies decrease the duration of surgery, soft tissue trauma and swelling, post-operative pain, and hospital stay. Adequate management of convexity meningiomas enhances the potential for patients to return to their pre-morbid lifestyle and job occupation. Lastly, maximal removal of the tumor and its meningeal origin improves the chances of patients progressing without tumor recurrence.