Unusual Multinucleated Giant Cell Reaction in a Tongue Squamous Cell Carcinoma: Histopathological and Immunohistochemical Features.

Multinucleated giant cell (MGC) reaction in oral squamous cell carcinoma (OSCC) usually represents a stromal foreign body reaction to keratin from neoplastic epithelial cells. We describe and illustrate by double immunohistochemistry a case of a tongue squamous cell carcinoma (SCC) in a 70-year-old female patient, with a copious MGC reaction not associated to keratin, showing a histopathological pattern not described before. The MGCs were directly associated with neoplastic cells, which are phagocytosed by the MGCs. Immunohistochemistry for CD68, AE1/AE3, CD163, CD11c, RANK, RANK-L, OPG were performed, as well as double staining for CD68 and AE1/AE3 to better illustrate the relationship between MGCs and neoplastic cells. The clinical and biological significance of this pattern of MGC reaction in OSCC needs to be better elucidated.