Antrochoanal polyps.
Inflammatory polyps that arise in the maxillary antra may extend into the nasal cavity and result in nasal obstruction. In some instances a combination of roentgenographic findings is helpful in diagnosis. This combination includes diminished aeration of the involved maxillary antrum, expansion of the antrum, and a soft tissue mass within but not arising from the nasopharynx.
D000293:Adolescent; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008443:Maxillary Sinus / Q000000981:diagnostic imaging; D009296:Nasal Cavity / Q000000981:diagnostic imaging; D009298:Nasal Polyps / Q000000981:diagnostic imaging*; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging; D011859:Radiography