Dentinogenic ghost cell tumor with focal atypical features suggesting ghost cell odontogenic carcinoma: Report of a challenging diagnosis.

Dentinogenic ghost cell tumor (DGCT) represents a rare benign odontogenic neoplasm that can appear in a central or peripheral form and may rarely undergo malignant transformation to ghost cell odontogenic carcinoma (GCOC). We aim to report a case of a central DGCT with focal cytological malignant aspects. A 24-year-old woman exhibited a painful enlargement and dental mobility in the left posterior maxilla for about one year, which appeared as an expansive well-defined hypodense maxillary image with hyperdense foci invading ipsilateral maxillary sinus. Incisional biopsy showed a predominantly solid hyperchromatic basaloid epithelium presenting cellular pleomorphism and mitotic activity, admixed with abundant ghost cell aggregates and dentinoid material. The lesion was immunopositive for p53 and had 21% of Ki-67 proliferation index (PI). These microscopic features suggested initially a GCOC diagnosis. Partial left maxillectomy was performed without complications. The surgical specimen presented an exuberant variation of the epithelial parenchyma, including ameloblastomatous, fusiform, and cribriform areas, with numerous ghost cells and dentinoid material, lacking any signs of malignancy. The final diagnosis was DGCT. The patient is in a strict regular follow-up for over two years, and there are no signs of recurrence.