By Jason Wasserman MD PhD FRCPC
September 6, 2023
We do not know what causes a bile duct adenoma.
Most bile duct adenomas do not cause any symptoms and are found incidentally (by accident) when imaging such as an ultrasound, MRI, or CT scan is performed or when the liver is directly examined during a surgical procedure.
Bile duct adenoma is usually diagnosed after part, or all of the tumour is removed and the tissue is examined under a microscope by a pathologist. These tumours are commonly an unexpected finding during surgery and the tissue is sent for an intraoperative or frozen section examination to rule out more serious conditions that can resemble a bile duct adenoma (such as a metastasis to the liver).
When examined under the microscope, a bile duct adenoma is made up of small cells that connect to form circular structures called ducts. The ducts often group together to form a round nodule just under the capsule (outer surface) of the liver. The stroma (connective tissue) surrounding ducts may be described as fibrotic or reactive. Larger channels called portal tracts may also be seen inside the nodule.