Benign odontogenic ghost cell lesions revisited and new considerations on dysplastic dentin

Objectives This study aimed to revisit benign odontogenic ghost cell lesions (BOGCL) by hematoxylin and eosin staining and immunohistochemistry. Materials and methods Thirty cases of calcifying odontogenic cyst (COC) and 6 cases of dentinogenic ghost cell tumor (DGCT) were selected for histopathological and immunohistochemical analysis. Sections stained for cytokeratin (K) 14, K-19, amelogenin, collagen type 1 (COL-1), and dentin matrix acidic phosphoprotein 1 (DMP-1) were evaluated using qualitative analysis. Sections stained for Ki-67 and minichromosome maintenance protein-2 (MCM-2) were evaluated using semi-quantitative analysis. Results A morphologic overlap was noticed in all BOGCL. Moreover, no differences were detected in the expression of K-14 and K-19. The expression of proliferative markers Ki-67 and MCM-2 was similar between cystic and tumor lesions ( p > .05). The presence of COL-1 and absence of amelogenin in the so-called dysplastic dentin, associated with its histologic pattern, suggest that this is in fact an enameloid-like tissue. Conclusions The dysplastic dentin should be considered an enameloid-like tissue in these lesions. Clinical relevance The similarity in histology, protein expression, and proliferative marker indices between COC and DGCT suggest that they are a sole entity and likely represent types of the same neoplasia.