Meningioma at 40x Magnification
The meninges are the three membranes that surround the brain and spinal cord. A meningioma is a type of frequently benign tumor that develops in the outermost of these membranes, the dura mater. The cells of origin of meningiomas are the arachnoid cap cells that line the inner dura mater, and therefore, the tumors can develop anywhere these cells are found. Oftentimes meningiomas are ovoid in shape, but those that form in some areas, such as the fold of the dura mater known as the tentorium, exhibit a form reminiscent of a dumbbell. Symptoms associated with the presence of a meningioma largely depend upon the site affected by the tumor, but may include localized or nonspecific headaches, spinal pain, blurred or lost vision, hearing loss, personality change, incontinence, apathy, sensations of numbness, and seizures.