CD163 and undifferentiated pleomorphic sarcoma: Among 247 patients with osteosarcoma, the median numbers of CD68+ and CD163+ macrophage infiltrations were approximately 110/mm2 and 150/mm2, respectively, which were lower than those of angiosarcoma, undifferentiated pleomorphic sarcoma, dedifferentiated liposarcoma, myxofibrosarcoma, pleomorphic liposarcoma, and leiomyosarcoma.