During the past 7 years, the author encountered 8 patients whose chief complaint was a swelling of the bone at the infraorbital region. Seven of the eight patients were operated on for removal of the bony bulge. In the five patients the anterior plate of the maxillary sinus protruded anteriorly associated with thinning of the bony plate, while in the other two cases were found an accessory maxillary sinus underneath the swollen bone. These findings are in contrast with those of pneumocele of the maxillary sinus in that the swelling is confined to the infraorbital region.
A search of literature revealed only one such case rei5orted by Cottle. This pathology may be called pneumosinus dilatans of the maxillary sinus.
The author inferred that such bulging of the anterior plate of the maxillary sinus is the result of unusually active pneumatization of the maxillary sinus creating prominent protrusion of the anterior wall of the sinus.