Granular cell odontogenic cyst: a unicystic ameloblastoma with late recurrence as follicular ameloblastoma.

This report is a follow-up of the original case of granular cell odontogenic cyst described by Gold and Christ in 1970. The lesion, originally treated by enucleation in 1965, recurred 18 years later as a follicular ameloblastoma with prominent plexiform and acanthomatous histologic patterns. No histologic evidence of granular cells was noted in the recurrent lesion. The recurrent ameloblastoma was treated by marginal resection of the body of the mandible and immediate reconstruction with an iliac bone graft. The anatomic restoration was excellent, and there is no recurrence 5 years postoperatively. This case supports the view that the granular cell odontogenic cyst is a unicystic (monocystic) granular cell ameloblastoma, and that the presence of granular cells in ameloblastoma is not a permanent feature and may be of little value as a prognostic indicator of aggressiveness.