ACTA1 and neoplasm: Fig 1C and 1D show high cellularity of pyknotic atypical cells in low- and high-magnification photomicrographs stained with hematoxylin-eosin (HE). Immunohistochemistry showed that the tumor cells were diffusely positive for vimentin (Fig 1E), MDM2 (Fig 1F), and CDK4 (Fig 1G), partially positive for CD31 (Fig 1H) and CD34 (Fig 1I), and weakly positive for α-SMA (Fig 1J). Tumor cells were negative for S-100 protein (Fig 1K).