Local bile ducts dilatation with enhanced regions of thickening of the periductal parenchyma and atrophic changes at the same lobe of the liver in a 55 Y/O patient with jaundice and recent weight loss. These findings are consistent with periductal infiltrating cholangiocarcinoma (histologically proven).
This type of cholangiocarcinoma is characterized by growth along a dilated or narrowed bile duct without mass formation.