CNS tumor
Meningeal tumors
Meningioma
Topic Completed: 1 December 2014
Minor changes: 11 January 2021
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Meningioma [title] CNS
Table of Contents
Definition / general | Radiology description | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Kresak JL, Yachnis AT. Meningioma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumormeningiomageneral.html. Accessed January 22nd, 2021.
Definition / general
- Most common primary brain tumor (20 - 30% of brain tumors, 6 per 100K annually)
- Derive from arachnoid cap cells (associated with dura mater, choroid plexus)
- Grow along external surface of brain or within ventricular system
- Slow growing (may grow rapidly during pregnancy), symptoms vague or related to brain compression
- Usually adults
- Female predominance: 2/3 of cerebral meningiomas occur in women, 90% of spinal cord meningiomas occur in women
- Usually solitary; multiple tumors (seen in 1 - 6%) are occasionally associated with neurofibromatosis 2
- Three grades exist based on WHO criteria
- Most are WHO grade I (benign)
- ~6% are WHO grade II (increased likelihood of recurrence)
- Rarely are WHO grade III (malignant with metastatic potential)
- Many variants of meningiomas exist
- Grade I variants
- Angiomatous:
- 2% of all meningiomas
- Vascular component should exceed 50% of total tumor area
- Meningothelial cells are wrapped around small blood vessels
- Also has large vessels
- Mean Ki67 index is 2%
- Do not recur if entirely resected (Am J Surg Pathol 2004;28:390)
- Differential diagnosis includes hemangioblastoma, which stains positive with inhibin and NSE
- Fibroblastic:
- Firm tumors composed of spindle cells with indistinct cell boundaries
- Sheet-like architecture, may not contain lobules or classic meningothelial whorls
- Resemble schwannoma or solitary fibrous tumor but are focally EMA+, often have thick bundles of collagen
- Lymphocyte rich
- May be associated with Castleman disease or other hematopoietic neoplasm
- Meningothelial:
- Most common variant
- Syncytial and epithelial cells, indistinct cell borders and classic whorls
- May have sparse psammoma bodies
- Metaplastic:
- May contain foci of bone, cartilage or fat
- Microcystic:
- Rare to have extensive microcystic formation
- Cells have elongated processes and loose myxoid background
- Overall resembles microcysts
- Has focal "classic" features
- Variable pleomorphism
- No cords or trabeculae, no inflammatory infiltrate
- EM shows extracellular microcysts
- Psammomatous:
- Found in spinal region
- Numerous psammoma bodies
- Secretory:
- Eosinophilic secretions
- May have cytologic atypia
- May secrete CEA
- Transitional:
- Meningothelial and fibroblastic features
- Usually prominent whorls, psammoma bodies and clusters of syncytial cells
- Angiomatous:
- Grade II variants
- Grade III variants
Radiology description
- Strong and homogenous enhancement on MRI with contrast
- Usually display a "dural tail"
- Usually isodense with the gray matter on T1 weighted MRI
- May show a so called "CSF crest" around the tumor indicating its extra-axial location
Case reports
- 11 year old boy with pediatric microcystic meningioma (Childs Nerv Syst 2013;29:361)
- 22 year old man with microcystic meningioma, WHO grade I (Case #104)
- 37 year old woman with dural based intracranial masses (Arch Pathol Lab Med 2005;129:e173)
- 61 year old man with left brain mass (Case #373)
- Angiomatous meningioma of orbit mimicking as malignant neoplasm (Orbit 2011;30:183)
- Breast carcinoma metastatic to meningioma (J Clin Neurosci 2015;22:268)
- Dumbbell meningioma of the upper cervical spinal cord (J Orthop Sci 2013;18:1042)
- Leukemic infiltrate within a meningioma (Am J Surg Pathol 2001;25:127)
Treatment
- Observation - if asymptomatic
- Gross total resection is usually curative
- Postoperative radiation if incompletely excised or WHO grade II or III
Gross description
- Rounded and well circumscribed
- Attached to dura
- Tumor separates readily from brain
- May grow en plaque (along dural surface) and cause reactive (hyperostotic) bone changes
Gross images
Images hosted on other servers:
Tumor displaces brain without invading
Compression of underlying cortex
Resected tumor
Adherent to falx cerebri
Microscopic (histologic) description
- Arachnoid plane exists between meningioma and CNS parenchyma
- Lobulated architecture, often contain "meningothelial" whorls
- Syncytial cells with indistinct cell membranes
- Eosinophilic cytoplasm
- Round uniform nuclei, intranuclear pseudoinclusions common
- May contain psammoma bodies
- Xanthomatous degeneration, moderate nuclear pleomorphism and metaplasia may be seen but have no prognostic significance
- Rarely necrosis or extensive hemorrhage
Microscopic (histologic) images
Cytology description
- Small to medium sized cells with moderate well defined cytoplasm and short processes
- Some nuclei have grooves
- Cells form focal whorls
- Variable psammoma bodies
Cytology images
Case #104
Mass at base of skull with inclusions and grooves
Images hosted on other servers:
Meningothelial tumor
Positive stains
Electron microscopy description
- Tightly interdigitating cellular processes held together by desmosomes
Molecular / cytogenetics description
- Mutations or deletions of NF2 gene seen in sporadic meningiomas and those associated with NF2
- Monosomy 22
Differential diagnosis
Additional references
