CD68 and CR3/43 immunohistochemical expression in secretory meningiomas.
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.


CONCLUSIONS
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.
Caffo
Mariella
M
Neurosurgical Clinic, Department of Neurosciences, Psychiatry and Anaesthesiology, University of Messina School of Medicine, Messina, Italy.
Caruso
Gerardo
G
Germanò
Antonino
A
Galatioto
Salvatore
S
Meli
Francesco
F
Tomasello
Francesco
F
D000368:Aged; D015703:Antigens, CD / Q000378:metabolism*; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D016177:Macrophage-1 Antigen / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008579:Meningioma / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D016177:Macrophage-1 Antigen; C067980:CD68 antigen, human; D000097382:CD68 Molecule