Ameloblastoma : Immunohistochemistry

Ameloblastomas are keratin positive. The tumor cells express CK5 and CK14. The stellate reticulum cells co-express CK8, CK18, and CK19. A continuous layer of laminin is present around the tumor cells. Calretinin is positive in the stellate reticulum cells, where as it is negative in keratocyst which enters into the differential diagnosis. Granular cell ameloblastomas are keratin positive, S-100 protein negative, and CD68 positive.