Diagnostic Yield of Small Histological Cores Obtained via a New EUS-guided Fine Needle Biopsy System

Aim: To assess the clinical utility of a novel EUS-guided fine needle biopsy (FNB) system.Methods: A retrospective review of consecutive patients undergoing EUS-guided tissue sampling of solid lesions using the Beacon Sharkcore fine needle system. At least one pass was submitted for histology and diagnostic accuracy was compared to standard cytology specimens sent simultaneously from the same tissue target using a conventional fine needle aspiration (FNA) technique.Results: Fifty-three patients underwent 59 EUS-FNB procedures. Cytology was simultaneously sent in 35 cases. Of the 59 FNB and 35 FNA specimens, 52 (88.1%) and 28 (80%) were adequate for diagnostic examination (includes four and seven atypical/suspicious for adenocarcinoma, respectively). The sensitivity, specificity and accuracy for malignancy of FNB and FNA were 81.5% vs. 78.2%, 100% vs. 91.7%, and 88.1% vs. 82.9% (p=0.516), respectively. Out of the 14 cases that were atypical/suspicious for adenocarcinoma or non-diagnostic on FNA cytology, 11 cases obtained definite diagnoses on FNB histology (three adenocarcinomas, two neuroendocrine tumors, one renal cell carcinoma, one leiomyoma, one serous cyst adenoma, one ectopic pancreas and one chronic pancreatitis). No complications were reported after FNA or FNB.Conclusion: Although there was no significant difference in the diagnostic yield for malignancy between FNB and FNA, both techniques were safe and some of the small histological cores obtained via FNB yielded a more definitive diagnosis.