Todani type III: like biliary dilatation with duodenal prolapse—a case report

Abstract Background Biliary dilatation is a rare disease involving intrahepatic and extrahepatic biliary tract abnormalities. With the development of imaging technology, an increasing number of special cases have been diagnosed, which poses a challenge to the traditional classification method. Case presentation A 50-year-old woman was admitted to the hospital due to right upper quadrant pain for more than 10 days. The patient had previous episodes of similar symptoms, which were relieved after symptomatic treatment at a local community hospital. After the symptoms developed, she underwent a computed tomography scan at the local hospital, which showed biliary dilatation; thus, she was referred to our hospital for further treatment. After admission, her magnetic resonance imaging examination also suggested biliary dilatation, but abnormal signals were found in her duodenum. First, a duodenal diverticulum was considered. Later, endoscopic ultrasonography was conducted, and the results suggested that the dilated biliary tract had herniated into the duodenum. This type of lesion is most closely classified as a Todani type III lesion. The patient finally underwent choledochectomy and Roux‑en‑Y hepaticojejunostomy, and the postoperative pathology was consistent with our preoperative diagnosis. The patient was followed up for approximately 2 years, and no obvious postoperative complications were found. Conclusions The manifestations of this case are relatively rare and involve one of the undiscussed categories of the Todani classification system; therefore, this case has certain clinical value. Moreover, there is no report similar to this experience in the previous literature.