PAPILLARY CARCINOMA OF THE THYROID WITH EXUBERANT NODULAR FASCITIS-LIKE STROMA

We describe a rare case of papillary carcinoma with extensive prolifer ation of stromal cells. The stromal cells were immunocytochemically po sitive for vimentin, alpha-smooth muscle actin and desmin, but negativ e for cytokeratin, epithelial membrane antigen, S-100, thyroglobulin a nd CD34. These results and the ultrastructure of the stromal cells, wh ich exhibited the characteristics of both fibroblasts and smooth muscl e cells, indicated an origin from myofibroblasts. We conclude that myo fibroblastic proliferation may contribute to the stromal response in t he slow growth of the papillary carcinoma.