Related Experiment Video
Updated: Dec 18, 2025
Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas
Published on: January 17, 2018
Pathology of meningiomas
David A Solomon1, Melike Pekmezci1
1Division of Neuropathology, Department of Pathology, University of California San Francisco, San Francisco, CA, United States.
Abstract:
Meningiomas are a diverse group of neoplasms that exhibit a wide range of morphologies and clinical behavior. They are generally accepted to originate from arachnoid cap cells within the leptomeninges. Classic histologic features include whorl formations, psammoma bodies, nuclear holes, and nuclear pseudoinclusions. Meningiomas are classified as benign, atypical, or anaplastic (grades I, II, or III) based on histologic features including mitotic activity, brain invasion, and presence of other minor criteria. There are numerous histologic variants of meningiomas, and some are associated with worse clinical outcomes and therefore are assigned a higher grade. The majority of meningiomas show diffuse positivity for vimentin and epithelial membrane antigen, supporting the dual mesenchymal and epithelial nature of meningothelial cells. The presence of an elevated proliferation index (as measured by Ki-67 immunohistochemical stain) and loss of progesterone receptor expression are associated with the higher grade. Pathologic features including histologic variants, grading criteria, and ancillary tests such as special and immunohistochemical stains are discussed.
Insights
Meningiomas, tumors originating from arachnoid cap cells, are classified by histologic features and grade. Understanding these pathological features is crucial for diagnosis and prognosis.
Area of Science:
- Neuro-oncology
- Pathology
Background:
- Meningiomas are neoplasms originating from arachnoid cap cells.
- They present diverse morphologies and clinical behaviors, classified into grades I, II, or III.
Purpose of the Study:
- To discuss the pathological features of meningiomas.
- To highlight the importance of histologic variants, grading criteria, and ancillary tests.
Main Methods:
- Review of classic histologic features (whorls, psammoma bodies).
- Classification based on mitotic activity, brain invasion, and minor criteria.
- Immunohistochemical staining for vimentin, epithelial membrane antigen, Ki-67, and progesterone receptor.
Main Results:
- Meningiomas exhibit characteristic histological features.
- Grading correlates with mitotic activity and invasion.
- Vimentin and EMA positivity support dual cell nature.
- Elevated Ki-67 and loss of progesterone receptor indicate higher grade.
Conclusions:
- Pathological assessment is key for meningioma diagnosis and grading.
- Histologic variants and immunohistochemistry aid in determining prognosis.
- Accurate grading guides clinical management and predicts outcomes.
