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Cellular components of microvascular proliferation in human glial and metastatic brain neoplasms. A light microscopic
P Wesseling1, J J Vandersteenhoven, B T Downey
1Department of Pathology, University Hospital Nijmegen, The Netherlands.
Abstract:
Since the origin of cells contributing to microvascular proliferation (MVP) in glial neoplasms is unsettled, a light microscopic and immunohistochemical study for vascular smooth muscle cells and endothelial cells was performed in formalin-fixed, routinely processed brain tumor biopsy material. MVP in glial neoplasms was compared with that in intracerebral metastatic carcinomas and in intracranial granulation tissue. On the basis of the degree of hyperplasia of hypertrophic cells in the microvascular wall, MVP was subjectively divided into mild, moderate, and glomeruloid (marked) proliferation. The relative contribution of vascular smooth muscle cells and endothelial cells to different degrees of MVP was estimated immunohistochemically using antibodies against alpha-smooth muscle actin and von Willebrand factor, respectively. Glomeruloid MVP occurred in 50% of the malignant glial neoplasms. Moderate MVP was found in most malignant gliomas and in some pilocytic astrocytomas. Glomeruloid MVP was present in peritumoral glial tissue in 4 out of 15 intracerebral metastatic carcinomas, while only mild to moderate MVP was found within these tumors. In granulation tissue MVP was mild. In glomeruloid and moderate MVP vascular smooth muscle cells were more hypertrophic and more numerous than endothelial cells. The contribution of hypertrophic vascular smooth muscle cells to mild MVP was variable. MVP in glial neoplasms was generally not accompanied by a matrix of fibrous stroma but was directly embedded in glial tissue. The architecture of this MVP suggested "in situ" proliferation of microvascular cells without migration of these cells into the surrounding tissue.
Insights
Microvascular proliferation (MVP) in brain tumors involves smooth muscle cells and endothelial cells. Smooth muscle cells are more numerous in moderate to glomeruloid MVP, suggesting in situ proliferation.
Area of Science:
- Neuro-oncology
- Vascular Biology
- Pathology
Background:
- The cellular origin of microvascular proliferation (MVP) in glial neoplasms remains unclear.
- Understanding MVP is crucial for diagnosing and treating brain tumors.
- MVP is a characteristic feature in various intracranial pathologies.
Purpose of the Study:
- To investigate the cellular origins of microvascular proliferation in glial neoplasms.
- To compare MVP in glial tumors with that in metastatic carcinomas and granulation tissue.
- To determine the relative contributions of vascular smooth muscle cells and endothelial cells to MVP.
Main Methods:
- Light microscopy and immunohistochemistry were employed on brain tumor biopsy samples.
- Antibodies against alpha-smooth muscle actin (for smooth muscle cells) and von Willebrand factor (for endothelial cells) were used.
- MVP was classified as mild, moderate, or glomeruloid based on cell hyperplasia.
Main Results:
- Glomeruloid MVP was observed in 50% of malignant glial neoplasms.
- Vascular smooth muscle cells were more hypertrophic and numerous than endothelial cells in moderate and glomeruloid MVP.
- MVP in glial neoplasms showed 'in situ' proliferation without significant cell migration.
Conclusions:
- Vascular smooth muscle cells play a significant role in the development of moderate to glomeruloid MVP in glial neoplasms.
- The findings suggest an intrinsic proliferation of microvascular cells within the tumor microenvironment.
- Distinguishing MVP origins aids in understanding tumor biology and potential therapeutic targets.