Multinucleated Giant Cells in Unicystic Ameloblastoma: A Very Rare (First?) Case Report and Review of the Literature

Background: Occurrence of giant cells has been reported in malignancies of pancreas, breast, and thyroid but rarely in benign tumors. However, giant cells were observed in some benign odontogenic neoplasms like solid multicystic ameloblastoma. Studies were carried out in the past to establish the origin and nature of these giant cells and the results were quite variable. Here, we present a very rare case of unicystic ameloblastoma, which revealed focal multinucleated giant cells in close proximity to the calcifications seen in the connective tissue. An attempt was made to identify the nature and origin of these giant cells by immunohistochemical staining, the cells were negative for cytokeratin and positive for CD68. This suggests that the giant cells were non-epithelial in origin and probably are of foreign body type and stromal in origin.