Fig. 1.

Graphical summary. The relationship between the six primary and recurrent pancreatic ductal adenocarcinoma (PDAC), with their histological and molecular features, is here shown. The cases have been numbered according to the text. The direction of the arrows indicates whether the first pancreatic ductal adenocarcinoma affected the head and then the tail (cases #1, #2, #4, #5, and #6) or vice versa (case #3). The lesions have been colored in red in case of “true” recurrence, in blue and green in case of independent lesions, and in yellow in case of  undetermined recurrence