Introduction The ability to provide definitive and timely histological diagnosis of malignancy in suspected malignant pancreaticobiliary lesions depends on high quality tissue sampling. We conducted a study to evaluate the diagnostic utility of endobiliary biopsy versus endoscopic ultrasonography-guided fine needle aspiration (EUS FNA) microcore biopsy.

Method We performed a retrospective search of our laboratory information management system for patients with suspected malignant pancreaticobiliary lesions who had endobiliary and EUS FNA microcore biopsies. The haematoxylin and eosin-stained slides were retrieved and reviewed, and assessed for adequacy; a biopsy is regarded as adequate if a pathological diagnosis can be rendered. All adequate biopsies are then categorised into whether a definitive diagnosis can be established (diagnostic) or not (non-diagnostic).

Results The search yielded 94 endobiliary biopsies and 78 EUS FNA microcore biopsies. 77 out of the 94 endobiliary biopsies were deemed adequate, and out of this 54 was diagnostic of malignancy (sensitivity 57%). In 11 cases where the endobiliary biopsy was not diagnostic, subsequent EUS FNA microcore biopsies provided a malignant diagnosis in 9. 96% of EUS FNA microcore biopsies were adequate and in 62 a malignant diagnosis could be established (sensitivity 83%). Cholangiocarcinoma was the pathological diagnosis in the majority of the endobiliary biopsies and there were two metastases from lung and two neuroendocrine tumours. The main malignant diagnosis in the EUS FNA microcore biopsies was adenocarcinoma of pancreaticobiliary-type, but also included neuroendocrine tumours, solid pseudopapillary neoplasm and adenosquamous carcinoma. There were also three metastases from the colorectum, kidney and breast.

Conclusion Our study indicates that EUS FNA microcore biopsy is more sensitive than endobiliary biopsy in the diagnosis of malignant pancreaticobiliary lesions. Because lesions are visualised, sampling is targeted and this provides high tissue yield enabling a malignant histological diagnosis to be rendered and reduces the need for repeated sampling. The tissue sample is also amenable to immunohistochemical staining which is important in characterising suspected metastases. EUS FNA microcore biopsy has been demonstrated to be useful in sampling suspected primary biliary neoplasm¹. As such, we believe that EUS FNA should be the standard method of tissue sampling in suspected malignant pancreaticobiliary lesions.

Reference

1. . Weilert F, Bhat Y, Binmoeller K, et al. EUS-FNA is superior to ERCP-based tissue sampling in suspected malignant biliary obstruction: results of a prospective, single-blind, comparative study. Gastrointest Endosc2014;80(1):97–104.

Disclosure of Interest None Declared