Fig. 2. Microscopy of extramedullary plasmacytoma of the thyroid. (A) Sheets of plasma cells infiltrating the thyroid parenchyma with few entrapped atrophic thyroid follicles (H&E, ×100). (B) Sheets of plasma cells with some binucleated forms (H&E, ×400). (C) Many lymphoid follicles with germinal centers (H&E, ×100). (D) CD138-positive tumor cells on immunohistochemistry.