Proptosis secondary to pneumocele of the maxillary sinus.

The third known case of a pneumocele of the maxillary sinus is reported. Radiographic findings included hyperlucency of a maxillary sinus with generalized expansion of its borders. Bone dehiscence was also visible with tomography. The present case emphasizes a gradual onset of clinical signs and manifested primarily by proptosis. Possible mechanisms in the production of this deformity are discussed.