The concept of Macroscopic On-site Evaluation (MOSE) was introduced in 2015 when the endoscopist observed better diagnostic yield when the macroscopically visible core on MOSE was superior to 4 mm. Recent studies suggest that MOSE by the endoscopist may be a good alternative to Rapid On-Site Evaluation (ROSE) and some classifications were published. Few studies have assessed the adequacy of histologic cores in MOSE during endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS- FNA/FNB). The aim of this study was to evaluate the performance of MOSE with multiple EUS-FNA/FNB needles (19G, 20G, and 22G) in practice.
Patients and Methods:
This multicentric prospective study conducted in 16 centers in 3 countries (Egypt, Iraq and Morocco) included 1008 patients with pancreatic, biliary, or gastrointestinal pathology who were referred for EUS examination. We prospectively analysed the MOSE according to 2 classifications to determine the adequacy of the histological core samples. Data management and analysis were performed using Statistical Package for Social Sciences (SPSS) 27.
Results:
A total of 1108 patients were analysed and 1008 with cytopathology reports were included. 1074 solid lesions were biopsied, with 664 involving the pancreas (62%). The mean age was 59 ± 12 years and 509 patients (50.5%) were males. The mean lesion size was 38 ± 17 mm. The needle types used for EUS-FNB were Franseen (Acquire) (n=751, 74.5%), Microtech (n=96, 9.5%), Procore (n=40, 4%), and Medtronic (n=20, 2%), whereas for EUS-FNA the needles used were Expect (n=68, 6.7%) and Echotip (n=33, 3.3%). The needle sizes used in the procedures were 22G (93.4%), 20G (3.8%), and 19G (2.9%) with a median number of needle passes of 2 [1-4].
According to 2 classifications: 618 non-bloody cores (61.3%) and 964 good samples (95.6%) were adequate for histological evaluation by the endoscopist. Post-procedural adverse events (abdominal pain, small blood collection, and transient fever) occurred in only 33 patients (3.3%). The overall diagnostic yield of cytopathology was 95.5%. The cytological examination confirmed the diagnosis of malignancy in 861 patients (85.4%), and benign lesions in 102 cases (10.1%).
Statistical analysis showed a difference between needle types (p=0.035) with a high sensitivity of FNB (97%). The analysis of the relationship between the MOSE score and the final diagnosis showed a significant difference between the different scores of the MOSE (p < 0.001).
Conclusion:
In practice, MOSE is simple method that allows the endoscopist to increase the number of needle passes to improve sample quality. Our study demonstrated higher FNB sensitivity (97%) and confirmed the relationship between good cores by MOSE scoring and high cytopathology diagnostic yield.

Mahmoud Ameen

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