[About a cyst of frontal sinus (author's transl)].

A case of true cyst of frontal sinus has been reported. The authors pointed out the good exposure given by the coronal incision approach. Differential diagnosis was discussed, no finding mentioned was pathognomonic. Difference with mucocele was made by microscopic examination. Because the bone destruction of posterior wall of the frontal sinus, an exclusion of the sinus was performed without filling of the cavity. Good result was obtained one year after operation.