Mucocele is commonly seen in which sinus?

A mucocele of a paranasal sinus is an accumulation of mucoid secretion and desquamated epithelium within the sinus with distension of its walls and is regarded as a cyst-like expansile and destructive lesion. The frontal sinus is most commonly involved whereas sphenoid, ethmoid, and maxillary mucoceles are rare. The sinuses commonly affected by mucocele in the order of frequency are the frontal, ethmoidal, maxillary and sphenoidal. (Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 223)