Peritoneal seeding in intraductal papillary mucinous neoplasm of the pancreas patients who underwent endoscopic ultrasound-guided fine-needle aspiration: The PIPE Study

Background and study aims: There have been concerns about peritoneal seeding after endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of mucinous pancreatic cystic lesions. The aims of this study were to determine the frequency of postoperative peritoneal seeding in patients with intraductal papillary mucinous neoplasm (IPMN) who had undergone pre-operative EUS-FNA and to compare it with that of patients with IPMN who had surgery with no pre-operative tissue sampling. Patients and methods: A total of 175 patients who had undergone resection of IPMNs with pre-operative EUS-FNA (EUS-FNA group) were analyzed and compared with 68 patients who had undergone resection with no pre-operative tissue sampling (No Sampling group). Patient characteristics, pathology, and frequency of peritoneal seeding after surgery were analyzed and compared. Peritoneal seeding was diagnosed based on pathology or image findings. Results: The two groups were comparable with respect to sex, age, follow-up duration, involvement of the pancreatic head, involvement of the main duct, grade of dysplasia, and size of histologically proven branch-duct IPMNs. Four patients (2.3 %) with invasive IPMN developed peritoneal seeding in the EUS-FNA group, whereas three (4.4 %, two with invasive IPMN and one with high-grade dysplasia) developed peritoneal seeding in the No Sampling group (P = 0.403). No peritoneal seeding was noted during surgery in these cases. Except for one patient in the EUS-FNA group, no spillage occurred during resection in these patients. Conclusions: In this cohort of patients undergoing resection of IPMN, the difference in the frequency of peritoneal seeding in the EUS-FNA group and the No Sampling group was not significant.