TUMOR-RELATED VENOUS OBSTRUCTION AND DEVELOPMENT OF PERITUMORAL BRAINEDEMA IN MENINGIOMAS

OBJECTIVE: The exact pathogenesis of peritumoral brain edema (PTBE) in meningiomas is still unknown. A number of different pathophysiologica l hypotheses have been considered. A detrimental effect of tumor-relat ed venous obstruction has been suggested as one pathogenetic mechanism . We sought to characterize the significance of venous stasis in the d evelopment of PTBE in meningiomas. METHODS: Angiograms for 134 patient s with 136 intracranial meningiomas were analyzed. Pathological change s affecting cortical veins, sylvian veins, bridging veins, deep veins, transmedullary veins, and dural sinuses were evaluated. From preopera tive computed tomographic scans, the total tumor volume, the tumor/PTB E volume ratio (edema index [EI]), and the location of the edema were determined. For statistical evaluation, meningiomas associated with pa thological venous drainage were compared with size-matched controls. R ESULTS: The edema incidence and the mean EI were not different for men ingiomas with unselected signs of obstructed venous drainage, compared with controls. In particular, lesions with involvement of cortical ve ins, bridging veins, and dural sinuses showed no higher edema incidenc e. However, meningiomas associated with venous changes in sylvian vein s (EI = 4.9 versus EI = 2.7; P < 0.004) and with dysplastic transmedul lary veins (EI = 3.3 versus EI = 1.7; P < 0.04) showed significantly h igher mean EI values, compared with meningiomas without involvement of these vessels. CONCLUSION: Our data suggest that tumor-related venous obstruction does not play an essential role in the development of PTB E for the majority of meningiomas. For a small subgroup of meningiomas with involvement of sylvian veins or development of dysplastic transm edullary veins, changes in venous drainage may aggravate preexisting P TBE.