Fig. 2

Histopathology, immunohistochemistry and molecular analysis of the tumor. A Histopathology analysis showed the tumor was centered in the sub-epithelial stroma and was lined by intact squamous mucosa (HE × 100). B & C The tumor was composed of mature adipocytes and a few atypical, enlarged spindle cells with hyperchromatic nuclei (B: HE × 200 and C: HE × 400). D & E Immunohistochemical staining revealed the tumor cells were positive for S-100 and MDM2 (D: HE × 200 and E: HE × 200). F MDM2 gene amplification (red signal) was confirmed by fluorescence in situ hybridization (FISH) analysis