Fig. 2

Pathological characteristics of the tumor:

A, The gross tumor showed Clear boundaries on cut surface; B, The tumor showed solid and cystic structures, tumor cells were rich in eosinophilic cytoplasm. HE staining with magnification ×40; C, Solid areas: The tumor cells were arranged in a nest and sheet. HE staining with magnification ×100; D, Cystic areas: The tumor cells were arranged in hobnail-like, Foam cells and lymphocytes infiltration were observed in the stroma. HE staining with magnification × 100; E, The tumor cells were focal positive expression of CK20. Staining by the En Vision method with magnification ×40; F, The tumor cells were negative of CK7. En Vision method with magnification × 40