Figure 1

Characteristic of the primary cardiac osteosarcoma in our patient. (A) Echocardiography results, showing a mass in the left atrium with accelerated color flow across the mass, suggesting a hemodynamically significant obstruction. The mitral valve area was 2.5 cm². (B) Histopathologic examination, showing that, microscopically, the tumor was composed of a uniform population of large atypical cells with prominent nucleoli and an osteogenic sarcomatous element. Original magnification ×400; (C-F) Immunohistochemical results, showing that the tumor was strongly stained with antibodies to vimentin (C) and CD68 (E), weakly stained with antibodies to CD34 staining (D), and completely negative for S100 (F). Original magnification ×400. Bar, 100 μm.