Amyloid Deposits in Supratentorial Meningiomas: Clinicopathological and Immunohistochemical Study

ABSTRACT

Amyloidosis is the definition for a group of diseases that have, in common, the infiltration of one or more tissues by an abnormal protein material-the amyloid substance, which is detected histologically by their green polarization color after Congo red staining. Despite increased interest on basic nature of amyloidosis by recent immunohistochemical or experimental study, the knowledge about the incidence and neurotoxic effect of cerebral amyloid or concomitant occurrence with brain tumor is still inchoate. We examined the incidence and clinico-pathologic characteristics of the patients with amyloid deposits in supratentorial meningiomas. Particularly about their neurotoxic effect to adjacent brain is considered one of the possible cause of seizure in 33 patients who underwent resection surgery for meningioma at the Keimyung University during the past three years. The pathological review and subgrouping by histologic type were done in all 33 specimens with sufficient size of paraffin block, defined by their morphology and polarization color after Congo red staining for diagnosis of amyloid deposits localized in the tumor. Immunohistochemical studies using monoclonal antibodies for amyloid-A protein(AA) and beta-amyloid(A beta) were evaluated to identify subtypes of amyloidosis. The rate of incidence of amyloid deposit in meningioma was 21%, i.e. seven out of thirty three cases. All laboratory findings and clinical studies did not suggest a systemic form. Seizure occurrence was one out of seven cases(14%), which was of no statistical significance. Immunohistochemical study for AA subtype was all negative, but showed all positive for A beta protein around the vessels. Recent reports has also demonstrated that Amyloid precusor protein(APP) and A beta is related in Alzheimer's disease, hereditary cerebral hemorrhage with amyloidosis-Dutch type(HCHWA-D) and amyloid angiopathy. Our research data indicates that the incidence of amyloid deposit is as high as 21% in supratentorial meningiomas. It seems that it is one of the possible cause of seizure. Nonsystemic microdeposits of amyloid and their subtype and it's relationship to neurotoxic effect in meningiomas remain to be confirmed by immunoelectron microscopic examination or immunohistochemical methods.