Endoscopic ultrasonography-fine needle aspiration of solid pancreatic masses: Do we need the fourth pass? A prospective study.

Background: Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) is important for the differential diagnosis of solid pancreatic lesions. Sample adequacy is related to the number of needle passes, and European guidelines recommend three to four needle passes with a standard EUS-FNA needle. We aimed to evaluate the optimal number of passes with standard EUS-FNA needles in solid pancreatic lesions.

Methods: Patients with solid pancreatic masses without cystic component >20% on computed tomography scan, and without biliary metallic stents, or coagulation problems were included prospectively. Standard 22G needles were used (maximum four passes); each sample was paraffin-embedded and analyzed separately. Final diagnosis was established by EUS-FNA, repeat EUS-FNA, surgery, or follow-up.

Results: Sixty-one of 65 patients were included. The final diagnoses were adenocarcinoma (n = 44, 72%), neuroendocrine tumor (NET) (n = 10, 16%), metastasis (n = 1, 4%) and nonmalignant lesion (n = 6, 10%). Immunohistochemical staining was possible in 17 cases. The diagnosis was established by the first pass in 62% of cases (n = 38), by the second in 15% (n = 9), by the third in 15% (n = 9), and by the fourth in 3% (n = 2). The diagnostic accuracy for all four passes compared to the first three passes was 95% vs 92% (P = .5). The contribution of the fourth pass was not different between adenocarcinoma and NET (2% vs 10%, respectively; P = .667).

Conclusion: Three passes with standard EUS-FNA was optimal for a specific diagnosis of solid pancreatic masses, regardless of the histological type of the lesion.