Genetic analysis of postoperative recurrence of pancreatic cancer potentially owing to needle tract seeding during EUS-FNB

Abstract

<b>Background and study aims</b> Needle tract seeding during endoscopic ultrasound fine-needle biopsy (EUS-FNB) remains a concern. We investigated whether such seeding occurred in a patient with pancreatic ductal adenocarcinoma (PDA). <b>Patient and methods</b> Surgically resected and EUS-FNB-derived specimens were genotyped to determine if a gastric wall tumor that emerged 3 years after curative resection of an early-stage PDA was clonally related to the original tumor. <b>Results</b> The gastric tumor histologically resembled the primary PDA; the lesions also shared <i>KRAS</i> , <i>SMAD4</i> , and <i>RNF43</i> mutations. Genotyping of the preoperative EUS-FNB specimen, in which cancer was not detected, nevertheless revealed mutations that were identical to those in the resected primary and recurrent tumors. While the primary PDA had a low frequency of mutant <i>SMAD4</i> , such mutations were highly prevalent in both the EUS-FNB and recurrent tumor specimens. <b>Conclusions</b> The genetic lineages of sampled tissues from our patient revealed that needle tract seeding may have incidentally occurred when a subset of neoplastic cells within a heterogeneous tumor ( <i>i. e.</i> , an aggressive clone) was targeted during EUS-FNB.