<prompt> Mucocele is commonly seen in sinus:FrontalMaxillaryEthmoidSphenoid  <response>: A mucocele is an epithelial lined, mucus containing sac completely filling the sinus and capable of expansion: Mucocele are most commonly formed in Frontal sinus followed by ethmoid, sphenoid and maxillary sinuses. Mucocele of frontal sinus presents as a swelling in the floor of frontal sinus above the inner medial canthus. It displaces the eyeball forward, downward and laterally. IOC CT scan TOC Endoscopic sinus surgery 