Figure 3.

Histological features illustrating the mixed components of the tumor. (A) Both the exophytic and morally invasive components contained prominent sarcomatoid elements, in the form of spindle and pleomorphic tumor cells with prominent mitotic activity; (B) minor component of the tumor showed osteogenic differentiation with formation of malignant osteoid; (C) the carcinoma component, constituting about 10% of the entire tumor, had morphological features characteristic of biliary adenocarcinoma with tumor cells being cuboidal and the overall architectural pattern being papillary; (D) the underlying bile duct epithelium showed foci of low and high grade dysplasia. Hematoxylin and Eosin stain. Magnification: (A-C) is 100× and (D) is 40×.