Histopathological characteristics of eruption mesenchymal calcified hamartoma: two case reports

Odontogenic calcified masses were present in the opercula of lower first molars that were delayed in eruption. The masses were relatively small, opaque, white in color with a smooth texture. Histopathological examinations revealed that they contained osteodentin, cementum, and pulp-like components; however, not odontogenic epithelial cells or enameloid. Further, mesenchymal multinucleated giant cells and dysplastic dental matrices were observed in the connective tissues surrounding the masses. These clinical and histopathological findings disagree with the features of pericoronal odontogenic hamartoma lesions, including odontoma, ameloblastic fibroma, and ameloblastic fibro-odontoma. Therefore, we propose to categorize this odontogenic mass as a new variety of hamartoma, eruption mesenchymal calcified hamartoma.