History. The tumor which today is called adenomatoid odontogenic tumor (AOT) was probably first described by Dreibladt (1907, quoted in Thoma 1970), who called the tumor “pseudoadenoma adamantinum,” and then by Harbitz (1915), who called it “adamantine cystadenoma” (Gorlin and Goldman 1970). Because of its resemblance to ameloblastoma, AOT was long classified among the ameloblastomas. It was not until 1948 that the tumor, then called adenoameloblastoma, was recognized as being distinct from other odontogenic tumors (Stafne 1948). It was characterized as an epithelial odontogenic tumor without an inductive effect on the mesenchyma (Gorlin et al. 1961).