Pneumosinus dilatans: a discussion of four cases and the possible aetiology.

ABSTRACT

Pneumosinus dilatans is an abnormal dilatation of the paranasal sinuses, which contains only air and is lined by normal mucosa. It is a rare condition, the aetiology of which is unclear. We describe four patients who presented to our department with pneumosinus dilatans. The aetiology was either developmental hydrocephalus (n = 1), post-traumatic (n = 1) or idiopathic (n = 2). Two patients underwent surgery, and follow-up is at least 12 months to date. The radiological aspects of this rare condition and the possible aetiologies are discussed.