An atypical case of clear cell odontogenic carcinoma occurred in the mandible of a 50-year-old Japanese man. Microscopically, the tumor mainly consisted of clear, glycogen-rich epithelial cell nests, aggressively proliferated in the mandible and invading into the surrounding soft tissues. Within the tumor cell nests, clusters of ghost cells were observed in addition to occasional foci of microcystic degeneration. Hyaline, osteoid or dentinoid-like deposits were also demonstrated adjacent to the tumor cell nests. Dentinal tubules were clearly revealed in some of these structures. Hence, this tumor was regarded as an epithelial neoplasm with odontogenic ectomesenchyme induction.