Fig. 4

Histology (A-E) and ancillary studies (F–H) of case 2: A Scanning magnification of the wall showing irregular ossifications and calcifications and a variation of cellularity. B Periphery of the tumor with sparse intratumoral adipocytes (arrowheads) and adjacent regional adipose tissue (asterisk). C, D Higher magnification of A showing (C) areas of high cellularity with foci of cartilaginous differentiation (arrowheads) and osteoclast-like giant cells (asterisk) and (D) areas of lower cellularity with relatively bland small tumor cells in a myxoid and collagen-rich stroma. E Area of heterologous osteosarcomatous differentiation with markedly atypical tumor cells producing osteoid and SATB2 expression by immunohistochemistry (inset). F, G Immunohistochemical stainings showing strong nuclear positivity for mdm2 (F) and cdk4 (G). H MDM2 / CEN12 FISH showing uncountable green signals (MDM2) and increased red signals (CEN12)