Recurrent bilateral coronoid hyperplasia: an unusual case.

A case of bilateral coronoid hyperplasia is presented. The possible aetiology of this rare condition is discussed. This case is unusual in that true synovial joints were demonstrated bilaterally between the coronoid processes and the zygomatic bones and following a bilateral coronoidectomy, the coronoid hyperplasia with marked limitation of jaw opening fully recurred, which has not been described previously. After a further coronoidectomy with return of function to the temporomandibular joints, a change from a retrognathic mandibular relationship to a gross prognathic position occurred. The management problems encountered with this case are discussed along with a documented account of the treatment provided over a 12-year period.