Diagnostic yield of small histological cores obtained with a new EUS-guided fine needle biopsy system.

Background: As endoscopic ultrasound-guided tissue acquisition techniques evolve, there is increasing interest in obtaining optimal histological samples to improve diagnostic accuracy. In this study, we aimed to assess the tissue acquisition success rate and test performance characteristics of a novel endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) system.

Methods: We performed a retrospective review of consecutive patients undergoing EUS-guided tissue sampling of solid lesions using the SharkCore fine needle system in a tertiary referral facility. At least two passes were submitted for histology and diagnostic accuracy was evaluated. Comparison standard was based on final surgical pathology or minimum six-month clinical follow-up.

Results: Seventy-nine patients underwent 85 EUS-FNB procedures. Of the 85 histology specimens, 78 (91.7%) were adequate for diagnostic examination (includes six atypical/suspicious for adenocarcinoma). The sensitivity, specificity, and accuracy for diagnosis of malignancy with FNB were 87.1, 100, and 90.6%, respectively. Cytology was simultaneously sent in 43 cases with the same needle in addition to histology. Out of the 14 cases that were atypical/suspicious for adenocarcinoma or non-diagnostic on cytology, 11 cases (78.6%) achieved definite diagnoses on histology. The overall sensitivity, specificity, and accuracy for diagnosis of malignancy combining histology and cytology were 90.3, 100, and 92.9%, respectively. No complications were reported after the procedures.

Conclusion: In this initial experience with a new EUS-guided FNB system, obtaining small cores to submit for histological analysis was safe, technically feasible, and highly accurate. Most of the histological cores obtained via FNB yielded a definite diagnosis including in cases with equivocal cytomorphology. Further study is required to confirm these findings.