<prompt> The incidence of the mucocele is lowest inFrontal sinusSphenoid sinusMaxillary sinusEthmoid sinus  <response>: Paranasal sinus mucoceles most commonly occur in the third or fouh decades of life with a slight male predilection. The frontal sinus is most commonly affected followed by the ethmoid sinuses, with repos suggesting 70-90 of mucoceles occur in these locations.Ten percent of mucoceles occur in the maxillary sinus and the sphenoid sinus is involved rarely. 