Fig. 2

Histological and Immunohistochemical features of the neoplasm. a The bile duct wall and surrounding liver tissue were not invaded. (Scale bar = 1000 μm). b The neoplasm shows complex papillary structures, fine fibrovascular stalks. (Scale bar = 100 μm). c The tumor cells were abundant eosinophilic granular cytoplasm, round or oval nuclei, clear nucleoli. (Scale bar = 50 μm). d-h Tumor cells were positive for MUC5AC (d), MUC6 (e), CD117 (f), HepPar-1 (g) and the Ki-67 (h) index is relatively low. (All scale bars = 100 μm). i LKB1 staining was negative in the tumor cells. (Scale bar = 100 μm)