Ghost cell odontogenic carcinoma arising from recurrent dentinogenic ghost cell tumor: a case report

Ghost cell odontogenic carcinoma (GCOC) is an exceptionally rare malignant odontogenic neoplasm. Treacher Collins syndrome (TCS) is a rare craniofacial developmental disorder, and no biological association between TCS and GCOC has been established. A 63-year-old man with clinically diagnosed TCS (genetic testing declined) presented 3 years and 1 month after segmental mandibulectomy for a dentinogenic ghost cell tumor (DGCT). Computed tomography showed an ill-defined destructive mandibular lesion. Review of the 2022 specimen showed odontogenic epithelial components with ghost cells but no overt malignant cytology or destructive carcinoma-type invasion. The 2025 specimen showed destructive infiltrative growth, marked cytological atypia, mitotic activity, and retained ghost cells, supporting GCOC arising in recurrent DGCT. The Ki-67 labeling index increased from approximately 10% to 50%; the remaining immunohistochemical findings were considered ancillary. The patient underwent radical segmental mandibulectomy with negative margins and no immediate adjuvant treatment. At 1 year, no local recurrence was detected on clinical examination and cone-beam CT; systemic restaging had not been repeated. A structured literature search identified no previous report explicitly describing GCOC in a patient with TCS, supporting interpretation of the coexistence as a rare coincidental finding. The case highlights malignant transformation in recurrent DGCT, the primacy of conventional histomorphology in diagnosing GCOC, and the need for prolonged surveillance.