Figure 1.

Soft tissue vegetation in pericardial sac. A, MICE is a mixture of histiocytes, mesothelial cells, fibrin, adipocytes, and inflammatory cells without a vascular network (Hematoxylin and eosin stain, × 100). B, Mesothelial gland-like structure are admixed with numerous histiocytes (Hematoxylin and eosin stain, ×200). C, The mesothelial cells are strongly immunoreactive for AE1/AE3 while the histiocytes are negative (DAB stain, ×400). D, The histiocytes are diffusely immunoreactive for CD68 while the mesothelial cells are negative (DAB stain, ×200).