Destructive cysts of the maxillary sinus affecting the orbit.

Symptomatic maxillary sinus cysts are diagnosed less frequently than similar cysts of the frontal and ethmoidal sinuses and are rarely reported in the ophthalmic literature. Patients with cysts of the maxillary sinus may present to the ophthalmologist with proptosis, enophthalmos, diplopia, ptosis, epiphora, and, rarely, decreased visual acuity. Four patients with maxillary sinus mucoceles are presented; one of these patients had a concurrent retention cyst in the orbit. Clinical history, radiologic findings, and histopathologic mechanisms are discussed. Mucocele is a recognized complication of the Caldwell-Luc procedure and midface trauma. Blockage of the sinus ostia was the cause previously proposed to explain antral mucocele development. Clinical and histopathologic features may support more than one single mechanism for the pathogenesis of maxillary sinus cysts. Maxillary sinus mucocele or retention cysts should be considered in the differential diagnosis of exophthalmos or enophthalmos following blowout fracture of the orbital floor.