How accurate is preoperative diagnosis by endoscopic biopsies in ampullary tumours?

The benign or malignant nature of ampullary tumours has prognostic and therapeutic implications. On the other hand the difficulty of reaching a correct preoperative diagnosis in these lesions is well known, even when we have a histological study obtained by endoscopic biopsies.

We review all ERCP's in which biopsies of the papilla were taken, performed between January 1991 and September 2000. We analyse the concordance rate between preoperative diagnosis (endoscopic biopsies obtained during ERCP) and definitive diagnosis (surgical specimen) (n = 32), and the possible influence of previous sphincterotomy in our results.

In the 32 patients studied global accuracy between pre- and postsurgical diagnosis was 68.7%. This accuracy was markedly higher in the group with ampullary cancer (82.7%) than in the group with ampullary adenoma (50%) (p = 0.12). In the group of patients with sphincterotomy accuracy was 56.25% and increased up to 81.25% in the group of patients without sphincterotomy, although statistical significance was not reached (p = 0.25).

In our series, the accuracy of endoscopic biopsies is higher in the adenocarcinoma group than in the adenoma group, obtaining better results in patients without previous sphincterotomy. The impossibility of a preoperative and absolutely certain confirmation of the benign or malignant nature of ampullary tumours forces us to be cautious in deciding type of surgical resection.