MULTINUCLEATED GIANT-CELLS IN THYROID NEOPLASMS - A CYTOLOGIC, HISTOLOGIC AND IMMUNOHISTOCHEMICAL STUDY

OBJECTIVE: To evaluate the presence of multinucleated foreign body-typ e giant cells (MGCs) in papillary carcinoma (PC), follicular variant o f papillary carcinoma (FV) and follicular adenomas (FA) and to investi gate their origin by immunoperoxidase studies. STUDY DESIGN: The cytol ogic and histologic material of 10 PCs, 8 FVs, and 11 FAs were evaluat ed for the presence of MGCs. The immunohistochemical staining pattern of MGCs in paraffin-embedded tissue teas studied using cytokeratin, ep ithelial membrane antigen, thyroglobulin, vimentin, A-1 antichymotryps in, lysozyme and CD68. RESULTS: MGCs were demonstrated in 10/10 PCs, 5 /8 FVs and 0/11 FAs. In the immunostained sections, MGCs were negative for epithelial markers and positive for histiocytic markers. CONCLUSI ON: These results indicate that MGCs are histiocytic and frequently pr esent in PCs and FVs and usually absent from FAs.