A well defined multilocular radiolucent lesion in the poster…

A well defined multilocular radiolucent lesion in the posterior mandible is seen on a routine panoramic radiograph of a 42 year old patient. The patient reports no pain or swelling. Surgical enucleation is performed, and histology shows the cyst has a keratinized epithelial lining.  The lesion recurs within a year.  Which of the following is the most likely diagnosis?