Ghost cell odontogenic carcinoma transformed from a dentinogenic ghost cell tumor of maxilla after multiple recurrences.

Dentinogenic ghost cell tumor (DGCT), also referred to as odontogenic ghost cell tumor, is a rare tumor classified as a neoplastic variant of calcifying odontogenic cyst (COC). Ghost cell odontogenic carcinoma (GCOC) is the especially rare malignant counterpart of DGCT and COC. The case of a middle-aged male with a maxillary DGCT which transformed to GCOC after 5 recurrences during a 21-year period is presented. When the diagnosis of GCOC (first identified as malignant after 17-year recurrence) was made, the tumor cells showed more obvious atypia, necrosis, and numerous mitoses, and interestingly the ghost cell was hard to find and even disappeared. The significances in pathologic diagnosis and clinical treatment are discussed.