There are two reasons why keratocysts (Odontogenic Keratocystic Tumor, OKT) may recur.
The cystic lesion has not completely been removed and a recurrence develops as a result of epithelial remnants left behind. A new keratocyst develops from epithelial islands left behind after removal of the main cystic lesion.
A prospective study on 82 OKT’s revealed that in about 60% of the cases these islands are to be found in the area where the cyst is attached to the mucosa overlying the cyst. This is most often in the mandibular trigonal area or above and in the mucosa of the maxillary tuberosity.
Treatment should be aimed at complete removal of the main cystic lesion and elimination of the accumulation of epithelial islands in the overlying mucosa. For this reason the bony defect may be treated with Carnoy’s solution so as to eliminate possible epithelial islands left behind and equally important, excision of that part of the mucosa that is attached to the cyst. This protocol would be indicated for all cysts in the trigonal area with extension into the ascending ramus and large cysts in the posterior part of the maxilla, since 90% of those will be OKT’s. Small cysts in the dentate area are often not diagnosed as keratocysts and should be treated as ordinary cysts. When the histology comes back OKT, a wait and see policy is advised.