Epidemiology of meningioma
Meningioma accounts for about one-third of primary tumors of the central nervous system (CNS), occurring mainly in older individuals with a female predominance.
Cause of meningioma
The etiology of meningioma is unknown in most cases. However, there is a clear association with prior radiation exposure, which is associated with a latency period that can exceed 30 years. Meningiomas are a common manifestation of NF2-related schwannomatosis, and somatic mutations of the NF2 gene may also contribute to the development of sporadic meningiomas.
Pathology
Meningiomas are classified according to the World Health Organization grading system. WHO grade 1 lesions are benign and generally have a favorable prognosis, whereas atypical (grade 2) and malignant (grade 3) meningiomas are significantly more likely to recur.
Location of meningioma
Meningiomas can occur anywhere from the dura mater, most commonly in the skull. About 10 percent originate from the spinal cord.
Clinical presentation
Many meningiomas have a slow growth and are discovered incidentally during a neuroimaging study. These may be asymptomatic or minimally symptomatic. Symptoms of large tumors can vary considerably depending on the location of the mass.
Imaging
On MRI, a typical meningioma is an extra-axial mass with a dural base, iso-intense or hypo-intense to gray matter on T1, iso-intense or hyperintense on proton density and T2-weighted imaging, and associated with strong homogeneous contrast enhancement after gadolinium administration.
Differential diagnosis
The differential diagnosis of meningioma includes a wide range of neoplastic and non-neoplastic entities. However, these are rare and almost always diagnosed after tissue acquisition, due to their clinical and radiographic similarity to meningiomas.
Diagnosis
A definitive diagnosis of meningioma and its classification as benign, atypical, or malignant requires histological confirmation at the time of biopsy or surgery. For small and minimally symptomatic tumors, the diagnosis relies on characteristic imaging findings.
Source: UpToDate