Peritumoural brain oedema in intracranial meningiomas: Influence of tumour size, location and histology

Peritumoural brain oedema was examined retrospectively in 175 patients with 179 intracranial meningiomas. The influence of tumour size. location and histology were investigated. Tumour Volume and localization, and the presence of peritumoural brain oedema (PTBOe) were determined by computed tomography (CT). The oedema-tumour volume ratio was defined as Oedema Index (Oel). AU patients underwent microsurgical removal of the tumour. Surgically resected meningiomas were classified histopathologically based on criteria of the new World Health Organization (WHO) classification. A close relationship was found between the tumour size and the incidence of peritumoural oedema: with increasing size of me tumour the incidence of oedema also rises, the oedema index, however decreases. Frontobasal and temporobasal meningiomas showed a significant increase in the oedema incidence and the mean oedema index. If major parts of the surface of meningiomas were adjacent to subarachnoid cisterns only a slight tendency for the development of oedema was observed. WHO-III-meningiomas showed a significantly higher oedema incidence (61.1% vs. 94.4%; p < 0.004) and mean oedema index (Oel = 2.7 vs. 3.7; p < 0.0009) than WHO-I-meningiomas. Brain tissue was affected In 59 cases, 19 meningiomas with infiltration into adjacent brain parenchyma revealed a statistically significant increase in oedema incidence (94.7% vs, 51.7%: p < 0.0003) and mean oedema index (Oel = 3.9 vs, Oel = 2.2: p < 0.0001) when compared to tumours without any brain tissue involvement in the histopathological specimens, Tumours sith large volume, fronto-temporo-basal location and anaplastic histology were nor only associated with the highest incidence of oedema formation bur also presented with an overproportionate infiltrative growth. Thus, a disruption of the arachnoid or a true brain infiltration may be an essential factor for The development of a PTBOe.