Maxillary sinus retention cysts protruding into the inferior meatus.

Although most of the maxillary sinus retention cysts are asymptomatic, a few of them increase in size and cause symptoms. However, they rarely erode bony walls nor protrude into the inferior meatus. I present 2 cases with maxillary sinus retention cysts protruding into the inferior meatus by making a large defect on the medial wall of the maxillary sinus.