Figure 3

Hematoxylin and eosin stain from an optical microscope at low magnification (40×, a) and high magnification (400×, b) of the bile duct wall. In (a), the whole thickness of the wall is included in the view field; as specified in the image, the lumen of the bile duct is on the right side of the histological specimen, and it is covered by normal mucosa. In (b) there is a detail of the external side of the bile duct wall: perivascular and intravascular (arrow) invasion of metastatic cells are shown.