The pathogenesis of cysts accompanying intra-axial primary and metastatic tumors of the central nervous system

Recent reports have suggested that cyst formation accompanying astrocytomas in the central nervous system (CNS) is due to an edematous process caused by blood-brain barrier (BBB) disruption and not a result of necrosis. This study is performed to investigate whether the hypothesis of cyst formation based on BBB disruption also applies to various pathologically different in tra-axial gliomatous tumors and metastases. By chemical analysis, using imm unokinetic nephelometry, isoelectric focussing, cellulose acetate electroph oresis and a biuretic method, the concentrations of albumin, immunoglobulin G (IgG), IgA, alpha(2)-macroglobulin, IgM and total protein were measured and proportions of concentrations of these proteins were compared in cyst f luid, blood plasma and cerebrospinal fluid (CSF). Our data, based on the chemical analysis of cyst fluid and blood plasma of 37 patients, including 2 ependymomas tone cerebral; one thoracic), 3 oligod endrogliomas, 3 hemangioblastomas, 5 cerebellair astrocytomas and 1 cervica l, 1 giant astrocytoma grade one, 1 gangliocytoma, 1 neuroblastoma and 19 m etastases (five lung-; two renal-; three breast-; one melanoma-; one thyroi d metastasis and seven metastases of unknown origin) present high protein c oncentrations in the cysts with a highly similar spectrum of proteins in th e tumor cyst fluid and blood plasma, suggesting a BBB disruption followed b y exudation of plasma proteins into the brain parenchyma with formation of edema and transition of edematous tissue into a cyst accompanying the tumor . Although histopathologically different types of tumor tissue are involved , data suggests that the pathogenesis of cysts accompanying gliomatous tumo rs and metastases in the CNS is based on BBB disruption and consequent edem a, as is the case in the formation of cysts in anaplastic astrocytomas.