[Ameloblastoma formation in an extensive follicular cyst]

A case of an unusual extensive dentigerous cyst of the mandible with ameloblastic formations in the cyst wall is presented. The tumor was totally enucleated in a two-step conservative surgical prosedure over 14 months, whereby the continuity of the mandible was preserved. The patient has been followed for two years. There has been a complete bone regeneration and no recurrence of the tumor. The importance of biopsy of odontogenic cysts associated with mandibular third molars is stressed.