LAUSR

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant neoplasm characterized by the presence of ghost cells. It is considered to arise either de novo or from a preexisting benign precursor, calcifying odontogenic cyst (COC), or dentinogenic ghost cell tumor (DGCT). We report a case of a 44‐year‐old Japanese male with a left maxillary tumor. The patient received treatment to resect the left maxillary cyst 25 years prior; however, the details were uncertain. The tumor was resected with clear margins. Taken together with the results of histological and immunohistochemical examinations, the tumor was categorized between GCOC and DGCT, and we diagnosed the tumor as GCOC suggesting similarity to DGCT. Further, we focused on CTNNB1, which encodes β‐catenin and is frequently mutated in COCs. In this tumor, we identified CTNNB1 Ser33Cys, one of the mutations typically found in COCs. This finding suggests that CTNNB1 is a common target for the pathogenesis of tumors accompanied by ghost cells.