Background: Patients with papillary adenocarcinoma survive longer than do patients with other histologic types of bile duct tumors. We evaluated the usefulness of intraductal ultrasonography (IDUS) for predicting the histology.
Methods: Preoperative tumor assessment was performed by using IDUS through a percutaneous tract or the transpapillary route in 37 patients with extrahepatic bile duct cancer. In 30 of 37 patients, imaging results were compared prospectively with histologic findings in resected specimens. Probes 2.0 mm in diameter and 20 MHz in frequency were mainly used. When IDUS showed a "narrow-based polypoid pattern" or a "papillary surface pattern," the patients were judged as having papillary adenocarcinoma.
Results: The accuracy, sensitivity, and specificity of IDUS in predicting papillary adenocarcinoma were 90%, 89%, and 90%, respectively. When intraductal ultrasonography showed a papillary surface pattern or a narrow-based polypoid pattern, lymph node metastases and perineural invasion were rarely seen when compared with other patients with bile duct cancer (p < 0.05).
Conclusion: IDUS is useful for assessing the histologic type of bile duct cancer.