Macroscopic on-site quality evaluation of biopsy specimens to improve the diagnostic accuracy during EUS-guided FNA using a 19-gauge needle for solid lesions: a single-center prospective pilot study (MOSE study)

Background: Although rapid on-site cytologic evaluation provides high efficacy of EUS-guided FNA (EUS-FNA), its availability is limited. Alternatively, macroscopic on-site quality evaluation (MOSE) may increase the efficacy of EUS-FNA. Objective: To assess the efficacy of MOSE in estimating the adequacy of histologic core specimens obtained by EUS-FNA using a standard 19-gauge needle (19GN) for solid lesions. Design: A prospective pilot study. Setting: Tertiary-care referral center. Patients: One hundred patients with solid lesions (n = 111 lesions). Interventions: EUS-FNA using 19GN Main Outcome Measurements: The relation of a macroscopic visible core (MVC) in the FNA specimens on MOSE with histologic core and the diagnostic yields were studied. Results: The feasibility of EUS-FNA using a 19GN was 99%. The final diagnoses were malignancy in 83 lesions and benign in 28. MOSE revealed MVC in 91.1% with the median length of 8 mm. Histologic core was confirmed in 78.9%. The receiver-operating characteristic curve of the length of MVC for the presence of histologic core showed the cut-off MVC length of 4 mm with area under the curve of .893. Comparisons of per-pass diagnostic yields showed significantly superior histologic, cytologic, and overall diagnostic yields in MVC >= 4 mm as compared with < 4 mm. The multivariate analysis for false-negative pass identified lesion in the pancreas and MVC < 4 mm as significant risk factors. No adverse events were seen. Limitations: Single center, limited operators Conclusion: MVC of >= 4 mm on MOSE can be an indicator of specimen adequacy and can improve diagnostic yield; however, additional FNA may be recommended for pancreatic lesions.