Impact of Macroscopic On-Site Evaluation (MOSE) on Accuracy of Endoscopic Ultrasound-Guided Fine-Needle Biopsy (EUS-FNB) of Solid Lesions: a randomised controlled trial

Aims Endoscopic ultrasound (EUS) tissue acquisition requires rapid on-site evaluation (ROSE) to improve diagnostic yield with less needle passes; however, ROSE requires the presence of a cytopathologist and additional cost and time for slide staining and interpretation. Macroscopic on-site evaluation (MOSE) is the direct assessment of the tissue sample provided by EUS-guided fine needle biopsy (EUS-FNB) macroscopically, to detect whether it is sufficient or not. Aim of this study was to evaluate the efficacy of MOSE in terms of tissue acquisition and diagnostic accuracy for abdominal solid lesions.

Methods This is a prospective and comparative study including 148 consecutive patients performing EUS-FNB for pancreatic and extrapancreatic solid lesions, randomized by alternate allocation to macroscopic on-site evaluation (MOSE) (74 patients) or to a conventional technique (74 patients), with two passes each. MOSE samples were differentiated into score 0: no visible material, score 1: only necrotic or haematic material, score 2: white core tissue≤2 mm, or score 3: white core tissue>2 mm. The conventional technique consisted in pushing all the needle content into a test tube for evaluation by the pathologist. In both groups, a 22 Gauge Franseen-tip needle biopsy was used [1].

Results The overall diagnostic adequacy was 92.5% (137/148) and accuracy was 86.4% (128/148). The diagnostic accuracy was similar in the two groups: MOSE 87.8% (65/74 lesions), vs. conventional 81.0%, 60/74 lesions, p=0.34). Regarding diagnostic adequacy, the MOSE technique was 95.9% (71/74 passes) compared to 91.8% (136/148 passes) with the conventional technique, p=0.04. The accuracy increased according to the MOSE score evaluation: it was 49.3%, 68.9% and 81.3% in patients with score 1, score 2, and score 3, respectively. There was no statistically significant difference between the two groups with conclusive and inconclusive cytopathological results regarding size of the needle, number of needle passes, type of the needle and the specimen acquisition method.

Conclusions The MOSE score showed a comparable diagnostic accuracy to the conventional technique. However, MOSE allows endoscopists to perform an inspective evaluation of the material, tends to perform better than the conventional technique in terms of diagnostic adequacy, and may potentially reduce the number of passes.

Conflicts of Interest

Authors do not have any conflict of interest to disclose.

• References

• 1 Mohan BP, Madhu D, Reddy N, Chara BS, Khan SR, Garg G. et al. Diagnostic accuracy of EUS-guided fine-needle biopsy sampling by macroscopic on-site evalu- ation: a systematic review and meta-analysis. Gastrointest Endosc 2022; 96: 909-17.e11

Publication History

Article published online:
27 March 2025