Giant Cell Granuloma of the Jaws and Keratin-Positive Giant Cell-Rich Tumor of Bone and Soft Tissue.

Background: Different giant cell-rich tumors may occur in the jaws. Recently, a new condition known as keratin-positive giant-cell rich tumor harboring recurrent HMGA2::NCOR2 fusions has been described. Interestingly, the mononuclear cells of this tumor are immunoreactive with the AE1/AE3 keratin. Considering the similarities of central and peripheral giant cell granuloma of the jaws with the keratin-positive giant cell-rich tumor of the soft tissue and bone, we hypothesized whether the keratin-positive tumors could also occur in the maxillary bones.

Methods and results: An immunohistochemical investigation of AE1/AE3 in a cohort of 16 cases of peripheral and central giant cell granuloma of the jaws was carried out. None of the cases was keratin-positive.

Conclusions: Although no immunopositivity for keratin was observed in the present giant cell granulomas cohort, we cannot completely exclude the possibility of keratin-positive giant cell-rich tumors occurring in the jaws. Therefore, oral pathologists should be aware about this condition and further studies using cohorts from different laboratories are necessary.