Diagnosis of the depth of invasion of gallbladder carcinoma by EUS.

Background: The prognosis of gallbladder carcinoma is dismal and relates to the depth of invasion as expressed by the T factor in TNM staging. We evaluated the utility of endoscopic ultrasound (EUS) in the diagnosis of the depth of invasion of gallbladder cancer.

Methods: Thirty-nine patients who underwent both EUS and surgery were included in this study. The EUS images were classified according to the relation between tumor echo pattern and gallbladder-wall structure, and the resulting types were compared with depth of invasion as determined histologically. Based on the results, a set of diagnostic criteria is proposed.

Results: The EUS images were classified into four categories. Type A is a pedunculated mass with a fine-nodular surface and intact neighboring wall. Type B is a broad-based mass with an irregular surface and intact outer hyperechoic layer of the adjacent wall. In type C, the outer hyperechoic layer is irregular due to a mass echo, whereas, in type D, the outer hyperechoic layer is disrupted by a mass echo. Each of the four categories of EUS images correlated well with the histologic depth of invasion.

Conclusion: EUS is useful in the T staging of gallbladder cancer.