Expression of hard α-keratins in adenomatoid odontogenic tumor: a case study with immunohistochemical analysis

Abstract

Adenomatoid odontogenic tumor (AOT) is an uncommon entity of odontogenic origin, characterized by the formation of duct-like structures in the tumor. Although its histogenesis is still uncertain, it is also considered to be a rather hamartoma-like lesion. Here we report a case of AOT in a 22-year-old Japanese woman, the first documented case to have been analyzed for the presence of hard α-keratin (human hair protein). A positive reaction for human hair proteins was noted in the marginal area of calcified material, or at the interface or between areas of dystrophic calcification and columnar epithelial cells. Furthermore, melanin pigment was demonstrated histologically in this case, similar to several previously reported cases of AOT with melanin. This is the first reported case of AOT with hard α-keratin. These findings suggest that AOT may have the potential to differentiate into hair components. (Oral Med Pathol 2008; 13: 7-14 doi: 10.3353/omp.13.7)