Imaging description

Tumor is the primary consideration when an eccentric focal narrowing or mural-based filling defect is seen at endoscopic retrograde cholangiopancreatography (ERCP) in the distal common bile duct, but this appearance has also been described as a transient and presumably physiological phenomenon that likely reflects transient duct contraction or peristalsis (Figures 25.1–25.4).

Importance

Recognition of this pseudotumor may help avoid unnecessary testing or surgery.

Typical clinical scenario

In one series of eight patients with the appearance of a pseudotumor in the distal common bile duct [1], only one patient went to surgery (and no pathological abnormality was found). As such the anatomic basis of this pseudotumor appearance is largely speculative and it is difficult to draw general conclusions as to the typical clinical scenario. Many of the patients in this report had prior hepatobiliary pathology or intervention; the extent to which this may have altered motility or contraction dynamics in the distal common duct is unknown.

Differential diagnosis

Recent reporting of the pseudotumor of the distal common bile duct [1] likely reflects a contemporary update to earlier studies describing the so-called “pseudocalculus sign” in the distal common duct that may be seen on endoscopic, percutaneous, intra-operative, and MR cholangiopancreatography [2–5].