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Published on: January 9, 2019
CD68 and CR3/43 immunohistochemical expression in secretory meningiomas
Mariella Caffo1, Gerardo Caruso, Antonino Germanò
1Neurosurgical Clinic, Department of Neurosciences, Psychiatry and Anaesthesiology, University of Messina School of Medicine, Messina, Italy.
Objective:
Secretory meningiomas (SMs) are unusual benign meningiomas. SMs are highly vascularized lesions, with angiomatous features and a perivascular arrangement, and they are accompanied frequently by massive peritumoral edema. Microglia have been called the brain's immune system, although the specific role and prognostic significance of microglia remain uncertain. The objective of this study was to analyze the expression of CD68, a macrophage marker specific for resting microglia, and the expression of major histocompatibility complex Class II CR3/43 in SMs.
Methods:
From 1995 to 2002, six patients with SMs were treated surgically at our institution. Immunohistochemistry was used to analyze the expression of CD68 and CR3/43 in tumor specimens. The intensity of expression was graded semiquantitatively. A correlation between immunohistochemical expression and the occurrence of brain edema was studied.
Results:
CD68-positive mononuclear cells were observed in neoplastic tissue or around pseudopsammoma bodies and in perivascular areas, with minimal expression in one patient and moderate expression in three patients. CR3/43-positive complexes were detected in mononuclear elongated elements with ameboid extensions, presumably referable to cells at different stages of immunological activation phenomena, with minimal expression in two patients, moderate expression in one patient, and marked expression in one patient. Edema was severe in all patients. Therefore, it may be indirectly hypothesized that edema may not be correlated with the CD68 and CR3/43 immunohistochemical expression.
Conclusion:
Macrophage infiltration and major histocompatibility complex Class II immunoreactivity in this subtype of meningioma suggest the occurrence of an immune response in the presence of SM.
Insights
Secretory meningiomas show macrophage infiltration and major histocompatibility complex Class II expression, suggesting an immune response. Edema severity in these benign tumors may not correlate with these immune markers.
Area of Science:
- Neuro-oncology
- Immunohistochemistry
- Neurosurgery
Background:
- Secretory meningiomas (SMs) are rare, benign tumors often presenting with significant peritumoral edema.
- The role of microglia, the brain's immune cells, in meningiomas is not fully understood.
- Assessing immune markers may offer insights into SM pathogenesis.
Purpose of the Study:
- To investigate the expression of CD68 (a macrophage marker) and major histocompatibility complex Class II (CR3/43) in SMs.
- To explore the potential correlation between these immune markers and peritumoral edema.
- To determine if an immune response occurs within SMs.
Main Methods:
- Surgical specimens from six SM patients (1995-2002) were analyzed.
- Immunohistochemistry was employed to detect CD68 and CR3/43 expression.
- Expression intensity was semiquantitatively graded, and correlated with edema presence.
Main Results:
- CD68-positive cells were found in neoplastic tissue and perivascular areas.
- CR3/43-positive complexes, indicative of immune activation, were detected.
- All patients exhibited severe edema, with no clear correlation to CD68 or CR3/43 expression.
Conclusions:
- The presence of macrophages and MHC Class II suggests an immune response in secretory meningiomas.
- Further research is needed to elucidate the precise role of microglia and immune markers in SMs.
- The study indicates that edema severity may be independent of the analyzed immune markers.
