Unicystic adenoid ameloblastoma: A new variant?

Dentinogenic ghost cell tumor revisited from a single institution in China with focus on adenoid ameloblastoma-like features

OBJECTIVE

The present study aims to identify adenoid ameloblastoma (AdAM) from previously diagnosed cases of dentinogenic ghost cell tumor (DGCT), and gain insight to the possible relationship between AdAM and DGCT.

METHODS

DGCT cases diagnosed between 2006 and 2022 were re-examined with focus on the AdAM-like features.

RESULTS

A total of nine patients were included. Seven patients were males and two were females. The mean age was 38.0 ± 16.0 years. Five tumors occurred in the maxilla and four in the mandible, with a remarkable predilection for the posterior regions of both jaws. Microscopically, dentinoid material deposition was present in all cases. The ghost cells were absent in two cases. Rare ghost cells (<1%) were observed in three cases, and a higher proportion of ghost cells (5%-20%) were present in the remaining four cases. All cases showed prominent AdAM-like features, including duct-like structures, whorls/morules, and cribriform architecture. According to the diagnostic criteria proposed by the 2022 WHO classification, five cases without or with rare ghost cells were reclassified as AdAM. The other four cases including a higher proportion of ghost cells consisted of a mixture of DGCT and AdAM histopathologic patterns.

CONCLUSION

Our results confirmed that the AdAM-like features had been largely overlooked in the diagnosis of DGCT at our institution in the past. Whilst a subset can now be more accurately classified as AdAM, some tumors showed overlapping morphological features between AdAM and DGCT, suggesting that the two may represent a spectrum of the same entity.