In the liver metastasis, the tumor displayed columnar cell PTC areas (positive for TTF-1, TG, and BRAFV600E) merging with undifferentiated carcinoma (UC) areas (positive for TTF-1 and BRAFV600E; negative for TG).
In clinicopathological analysis, the high-TTF1 expression group showed a higher incidence of liver metastasis and lymphatic invasion than the low-TTF1 expression group (p < 0.05), and tended to have more frequent venous invasion than the low-TTF1 expression group.