Malignant meningioma
Encyclopedia
Malignant meningioma is a rare, fast-growing tumor
that forms in one of the inner layers of the meninges
(thin layers
of tissue that cover and protect the brain and spinal cord
). Malignant
meningioma
often spreads to other areas of the body.
The World Health Organization
classification system defines both grade II and grade III meningiomas as malignant. Historically, histological subtypes have also been used in classification including:
Benign or low grade meningiomas (WHO grade I) include meningothelial, fibrous, transitional, psammomatous, angiomatous, microcystic, secretory, lymphoplasmacyte-rich, and metaplastic.
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
that forms in one of the inner layers of the meninges
Meninges
The meninges is the system of membranes which envelopes the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.-Dura...
(thin layers
Thin layers
Thin layers are congregations of phytoplankton and zooplankton in the water column which were discovered with advances in instrumentation and deployment technologies allowed samples at the temporal and spatial scales where patterns were revealed. Although they may extend for kilometers, thin layers...
of tissue that cover and protect the brain and spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
). Malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
meningioma
Meningioma
The word meningioma was first used by Harvey Cushing in 1922 to describe a tumor originating from the meninges, the membranous layers surrounding the CNS ....
often spreads to other areas of the body.
The World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
classification system defines both grade II and grade III meningiomas as malignant. Historically, histological subtypes have also been used in classification including:
- clear cell (WHO grade II),
- chordoid (WHO grade II),
- rhabdoid (WHO grade III), and
- papillary (WHO grade III)
Benign or low grade meningiomas (WHO grade I) include meningothelial, fibrous, transitional, psammomatous, angiomatous, microcystic, secretory, lymphoplasmacyte-rich, and metaplastic.
External links
- Malignant meningioma entry in the public domain NCI Dictionary of Cancer Terms