Histopathology and prognosis in human meningiomas

Histopathological grading of human meningiomas is based on criteria adopted by the World Health Organization (WHO). However, interpretation of the defined histopathological criteria is often subjective. The aim of this study was to investigate the clinical and histopathological features in these tumours associated with patient survival. This enables evaluation of current grading guidelines and practice. In this study, 196 primary, intracranial, and consecutively treated patients from one institution were included. All histological sections were reviewed. Survival data were controlled with the Norwegian Cause of Death Registry. Falcine location, sheet-like growth, frequent mitoses, subtotal resection grade, and absence of psammoma bodies were strong prognostic factors. Of these factors, the latter two were statistically significantly associated with decreased time to recurrence in multivariate analyses. The WHO 2000 and 2007 classifications were associated with decreased time to recurrence. However, the grading criteria suggested by Ho et al. (2002) and in this study achieved stronger prognostic values. Easily recognizable histopathological criteria are essential in tumour grading. We suggest that any two of the following three variables can be used to recognize atypical (grade II) meningiomas: absence of psammoma bodies, presence of necrosis, and/or ≥4 mitoses per 10 high power fields.