[Pneumosinus dilatans]

Abstract

Pneumosinus dilatans is a localized abnormal dilatation of paranasal sinuses which contains only air and is covered with normal epithelium. We presented the X-ray, CT and MRI findings of three cases with pneumosinus dilatans secondary to arachnoid cyst and meningioma. When evaluating the patients with long-lasting symptoms, pneumosinus dilatans should be considered.