Protocol design Eligible patients will have tissue sampling performed using both techniques during ERCP, the first technique used being randomly assigned and immediately followed by the other one as well as biliary decompression. All specimens obtained will be subjected to cytopathological examination. After inclusion of the total number of patients, smears will be anonymized and analyzed for diagnosis, cell cellularity and quality. The final clinical diagnosis in each case will be based on cytologic results plus histological examination of biopsy specimens.