The Natural History of Petroclival Meningiomas: A Volumetric Study.

OBJECTIVES

This study characterizes primary petroclival meningioma growth rates, before intervention, using volumetric analysis. In addition, predictors of growth are analyzed.

METHODS

Patients with previously untreated petroclival meningiomas were retrospectively reviewed (1999-2015). Image analysis software was used to perform volumetric analyses of tumor size and growth. Three-dimensional segmentation volumetric analyses were compared with volumes estimated utilizing three orthogonal dimensions. Tumor growth was defined as a 15% increase in volume.

RESULTS

Thirty-four patients who underwent at least two magnetic resonance imaging (MRI) studies before intervention were included. The mean age was 55.2 years, and 65.7% were women. The mean tumor volume at presentation was 5.6 cm (range, 0.1-25.8 cm) as determined from segmentation volumetric analysis. At a mean follow-up of 44.5 months (range, 3.7-125.1 mo), 88.2% of tumors grew. The mean annual volumetric growth rate was 2.38 cm/yr (-0.63 to 25.9 cm/yr). Tumor volume, T2 hyperintensity within the tumor, peritumoral edema, and ataxia and/or cerebellar symptoms at presentation were all significantly associated with greater rates of tumor growth. Ultimately, 10 (29.4%) patients underwent treatment during the follow-up period.

CONCLUSION

Our experience demonstrates that the vast majority (88%) of untreated petroclival meningiomas grow; the mean volumetric growth rate was noted to be 2.38 cm/yr. We found a significant association between increased growth rate and larger tumor size at diagnosis, T2 hyperintensity within the tumor, peritumoral edema, and the presence of ataxia and/or cerebellar symptoms.