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Intraparenchymal Meningioma: Clinical, Radiologic, and Histologic Review
Shigeo Ohba1, Masato Abe2, Mitsuhiro Hasegawa1
1Department of Neurosurgery, Fujita Health University, Toyoake, Aichi, Japan.
Background:
Although meningiomas are usually attached to the dura matter, intraparenchymal and subcortical meningiomas do not show dural attachment.
Methods:
A total of 39 cases of intraparenchymal meningiomas including subcortical meningiomas were reviewed.
Results:
Compared with ordinary meningiomas, intraparenchymal meningiomas occurred more frequently in males and at younger ages. Unusual magnetic resonance imaging findings such as heterogeneous enhancement and cystic components were frequently recognized. Histologic analysis revealed half of the intraparenchymal meningiomas to be of the fibrous type, and approximately 20% of the tumors were diagnosed as World Health Organization grade II-III disease. Compared with sylvian fissure meningiomas, which also lack dural attachment, patients with intraparenchymal meningiomas were younger than those with sylvian fissure meningiomas. Gross total resection was performed more frequently for intraparenchymal meningiomas than for sylvian fissure meningiomas. More patients with intraparenchymal meningiomas than those with sylvian fissure meningiomas showed malignant phenotypes, and fibrous phenotypes were twice as common among intraparenchymal meningiomas as among sylvian meningiomas.
Conclusions:
Because of the unique features described earlier, which contrast with those of ordinary meningiomas, there is a possibility that intraparenchymal meningiomas are not precisely diagnosed. Collectively, the information collected from the study cases may facilitate the appropriate management of these rare tumors.
Insights
Intraparenchymal meningiomas, unlike typical ones, lack dural attachment and present unique characteristics. This study highlights their distinct features for better diagnosis and management of these rare brain tumors.
Area of Science:
- Neuro-oncology
- Neurosurgery
- Radiology
Background:
- Meningiomas typically attach to the dura mater.
- Intraparenchymal and subcortical meningiomas lack dural attachment, presenting unique diagnostic challenges.
Observation:
- A review of 39 intraparenchymal meningioma cases, including subcortical variants.
- These tumors occurred more frequently in males and younger individuals compared to typical meningiomas.
Findings:
- Unusual MRI findings like heterogeneous enhancement and cystic components were common.
- Histology revealed a high prevalence of fibrous type and a significant proportion of World Health Organization (WHO) grade II-III tumors.
- Intraparenchymal meningiomas were associated with younger patient age, more frequent gross total resection, and a higher incidence of malignant and fibrous phenotypes compared to sylvian fissure meningiomas.
Implications:
- Unique features of intraparenchymal meningiomas may lead to misdiagnosis.
- Understanding these distinct characteristics is crucial for appropriate clinical management and treatment strategies for these rare brain tumors.
