Persistent deciduous molar as an etiology for a maxillary sinus mucocele.

Mucoceles are accumulations of trapped mucus, forming cystic expansile lesions. Maxillary sinus mucoceles are rare amongst paranasal sinus mucoceles, usually being a late sequel of Caldwell-Luc surgery. We present a case of a maxillary sinus mucocele due to a persistent carious deciduous molar in a middle aged patient, reported to highlight its unusual etiology.