Clinico-pathological study of meningiomas with haemorrhagic onset

Background. Haemorrhage from meningiomas is rare and the underlying pathophysiological mechanisms remain to be determined. We sought to identify these mechanisms by studying clinical and histological records of 6 meningioma patients treated at our institution. Patients and methods. We retrospectively studied 6 patients with meningiomas whose acute onset was due to haemorrhage. We evaluated clinical features and imaging studies. The vascularity and proliferative nature of these tumours were examined immunohistochemically and tissue factor (TF) immunoreactivity was assessed. For comparison we evaluated 25 non-haemorrhagic meningiomas. Findings. At onset, the haemorrhages mimicked stroke in all 6 patients. On imaging studies, 3 of the haemorrhages were intra- and extratumoural, the other 3 were extratumoural only. Hyperintensity on T2-weighted MRI was a characteristic of these meningiomas. Histologically. they were of 3 subtypes. meningothelial (n = 3), transitional (n = 2). and anaplastic (n = 1). The MIB-1 labelling index of the 5 WHO Grade I meningiomas was 5.8 +/- 2.2. The mean number of CD31-positive blood vessels did not differ in haemorrhagic and non-haemorrhagic meningiomas. The TF-positivity rate of haemorrhagic meningiomas was higher than of non-haemorrhagic meningiomas. Interpretation. The proliferative nature of the meningiomas and TF expression in turnout cells may have contributed to the eventual haemorrhage of the meningiomas in our series.