Fig. 4

Histopathological and molecular findings of the new mesenchymal tumor types of the World Health Organization and novelties of previously recognized entities. A Epithelioid cells in a myxoid stroma with amianthoid fibers and scattered lymphocytes (HPS, magnification × 400). B Spindle and epitheliod cells (HPS, magnification × 400). C Desmin immunoexpression (magnification × 400). D EWSR1 rearrangement using FISH analysis showing split signals (3’EWSR1: red signals; 5’EWSR1: green signals). E Sheets of epithelioid cells (HPS, magnification × 400). F Myxoid change (HPS, magnification × 400). G Spindle cells and glial differentiation (HPS, magnification × 400). H Diffuse expression of ETV4 (magnification × 400). I Spindle cell neoplasm with fascicular pattern (HPS, magnification × 400). J Myogenic differentiation (HPS, magnification × 400, and insert desmin immunoexpression, magnification × 400). K Pleomorphic cells (HPS, magnification × 400). L Expression of myogenin (magnification × 400). M Sheets of poorly differentiated cells (HPS, magnification × 400). N Myogenic differentiation (HPS, magnification × 400). O Olig2 immunoexpression described in cases with PAX3 fusions (magnification × 400). P Myogenin immunoexpression (magnification × 400). Q Epithelioid cells (HPS, magnification × 400). R Spindle cells (HPS, magnification × 400). S Brachyury immunoexpression (magnification × 400). T Loss of INI1 expression in tumor cells (magnification × 400). Black scale bars represent 50 μm. Ch. chordoma, FISH fluorescent in situ hybridization, HPS hematoxylin phloxin saffron, IMT intracranial mesenchymal tumor, Rhabdomyos. rhabdomyosarcoma, sarc sarcoma