The contribution of endoscopy and biopsy to the diagnosis of periampullary tumors.

BACKGROUND AND STUDY AIMS

Endoscopy and biopsy from a suspicious Vater's papilla may establish an early preoperative diagnosis of a periampullary tumor. However, information regarding the diagnostic accuracy of this procedure is limited and variable. The aim of the present study was to evaluate retrospectively the accuracy of this procedure compared to that of other diagnostic methods.

PATIENTS AND METHODS

Among 928 patients referred to our institute for endoscopic retrograde cholangiopancreatography (ERCP), a suspicious Vater's papilla was seen in 28. In each case comparison was made between the pre-ERCP clinical diagnosis, endoscopic appearance, histologic interpretation of endoscopic biopsies, and the final diagnosis. Two patients in whom a final diagnosis was not available were excluded from the study.

RESULTS

A final diagnosis of an ampullary or periampullary carcinoma was established in 17 patients (65%), a carcinoma within an adenoma of the papilla in three patients (12%), and adenoma and a metastatic gallbladder carcinoma in one patient each. The remaining four patients (15%) were finally diagnosed as having "pseudotumors" (due to choledocholithiasis). Eight (38%) of the 21 patients with ampullary or periampullary neoplasm also had gallstones. A pre-ERCP diagnosis (by clinical evaluation and non-invasive imaging) of tumor versus choledocholithiasis was accurate in only 65% of all 26 patients. In these, the diagnostic accuracy of endoscopic appearance and endoscopic biopsy was 77% and 85%, respectively. Regarding the 21 patients with carcinomas, the diagnosis by endoscopic appearance was more accurate than that by endoscopic biopsy (90% vs 81%). Unlike the positive predictive values, the negative predictive values for malignancy were weak: 33% for the endoscopic appearance and 50% for the endoscopic biopsy.

CONCLUSIONS

Because of a high incidence of concurrent cholelithiasis, many patients with a periampullary tumor seen during ERCP are misdiagnosed earlier (by clinical evaluation and non-invasive imaging) as having choledocholithiasis only. However, the accuracy of endoscopy and biopsy is also limited. This limitation must be considered when evaluating the optimal management of patients with suspected periampullary tumor.