Biological Characterization of Odontogenic Ghost Cell Lesions: A Clinicopathological, Immunohistochemical and Molecular Study of a Unicentric Series of 69 Cases.

AIM: The present study aimed to contribute to the biological characterization of odontogenic ghost cell lesions (OGCL).

MATERIALS AND

METHODS

Sixty-nine OGCL consisting of 60 calcifying odontogenic cysts (COC) and nine dentinogenic ghost cell tumors (DGCT) were collected from a single center over a period of 63 years. The clinical, radiographic, and histopathological features were re-evaluated. Histochemical and immunohistochemical studies were performed in 37 COC and three DGCT. Molecular studies were performed in 17 COC to identify possible CTNNB1 gene mutations.

RESULTS

COC was more frequent in women, in the second decade of life, involved the anterior region of both jaws, and manifested mainly as a unilocular radiolucency. DGCT was more frequent in women, in the ninth decade of life, involved the anterior region of mandible, and manifested as irregular mixed lesions. The ameloblastic/ameloblastomatous epithelium and ghost cells stained positive for AE1-AE3 (40/40), amelogenin (40/40), β-catenin (40/40), E-cadherin (40/40), S100 (22/40), and vimentin (15/40) in both the studied entities. TOM-20 (40/40), BCL-2 (40/40), BRAF V600E (4/40), and p63 (1/40) were only positive in the ameloblastic/ameloblastomatous epithelium, and lysozyme (40/40) and CD68 (35/40) were positive in the ghost cells. No single-nucleotide variants were detected in CTNNB1, except for a change at codon 38.

CONCLUSIONS

The protein immuno-expression observed in ghost cells confirms an epithelial origin and suggests that these cells result from a degenerative process involving an increase in lysosomes and accumulation of proteins. Immuno-expression of β-catenin in the absence of CTNNB1 mutations suggests the presence of mutations in other genes associated with the WNT/β-catenin pathway.