Identification of GNAS and KRAS in EUS-guided fluid samples from the main pancreatic duct (MPD) accurately discriminates Intraductal Papillary Mucinous Neoplasm (IPMN) from other conditions with MPD dilatation

Aims To evaluate the diagnostic yield of GNAS or KRAS mutation analysis in EUS-guided liquid samples from the MPD to recognize IPMN in patients with dilated MPD.

Methods Patients with available GNAS/KRAS testing of pre-operative EUS-guided liquid samples from dilated MPD where retrospectively collected. GNAS (R201H and R201C) and KRAS (exons 12 and 13) point mutations were analyzed by dd-PCR and cold-PCR, respectively.

Results 15 patients were included: 10 (67%) IPMN, 4 (27%) CP without IPMN and 1 (6%) MPD obstructive dilatation. Point mutations in GNAS and/or KRAS were present in 8/10 (80%) IPMNs (GNAS mutations in 8/8, KRAS mutations in 2/8). Cytology of EUS-samples was available in 9/10 patients with IPMN. GNAS/KRAS mutations were present in 6/7 (86%) IPMN with mucinous cytology and in 2/2 (100%) IPMN with non-mucinous cytology. No association was found between GNAS/KRAS mutations and age, sex, side branch cysts coexistence, CP association, MPD diameter or grade of dysplasia. All patients without IPMN did not present GNAS/KRAS mutations. Sensibility, specificity and global diagnostic yield of GNAS/KRAS analysis for IPMN diagnosis were 80%, 100% and 86.7%, respectively.

Conclusions Identification of GNAS/KRAS mutations in EUS-guided fluid samples from the MPD is highly accurate for IPMN discrimination in patients with dilated MPD.

EUS: Endoscopic Ultrasound, IPMN: Intraductal Papillary Mucinous Neoplasm; MPD: Main Pancreatic Duct ([Fig. 1]).

Fig. 1

Conflicts of interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
14 April 2023