Macroscopic on Site Evaluation (MOLSE) vs Standard Specimen Acquisition of Solid Lesions During EUS-FNB

Endoscopic ultrasonography (EUS) with tissue acquisition (TA) is nowadays a well-established technique for the sampling of solid lesions pancreatic and non-pancreatic lesions. Actually the standard methods to obtain sampling in gastrointestinal (GI) and non-GI solid masses is the fine needle aspiration (FNA) performed by endoscopic ultrasonography (EUS). Its sensitivity, specificity and diagnostic accuracy for malignant cytology are actually reported of 85-95%, 95%-98% and 78-95% respectively. These data could be affected by the presence of cytopathologist in endoscopy room during the tissue sampling. The rapid on-site evaluation (ROSE) has been advocated to significantly increase EUS-FNA accuracy. To overcome this problem fine needle biopsy (FNB) for TA to obtain histological specimens was proposed. These needles allow as the acquisition of an histological specimen than the cytological one with FNA needles. Recently, the need to obtain a histological, instead of a cytological, specimen during EUS has become more urgent and necessary due to innovative oncological treatment options. An acquired histological specimen could avoid the need of a cytopathologist in the endoscopic room, diminishing costs, procedures time, number of passes and reducing the additional costs of a possible repeated EUS-FNA, in case of an inconclusive diagnosis. With the advent of FNB, the macroscopic on-site evaluation (MOSE) of the specimen by the endosonographer was proposed, resulting in a comparable alternative to ROSE.