EUS-guided Through-the-needle Microforceps Biopsy Outcomes

INTRODUCTION: The diagnosis of pancreatic cystic lesions (PCLs) is increasing due to improvements of cross-sectional imaging. It is mandatory, for appropriate management, to make an accurate diagnosis and risk stratification, since some of these lesions may harbor malignancy or have potential for malignant transformation and hence surgical resection is required. Diagnostic evaluation of PCLs can be challenging, requiring a combination of different methods. Usually PCLs are been initially detected by cross-sectional imaging. However, imaging alone has not been shown to reliably identify the underlying pathology in PCLs with a high degree of accuracy. Hence, Endoscopic ultrasound with fine-needle aspiration (EUS-FNA) is routinely performed. EUS-FNA plays an important role in cyst characterization since allows morphological examination (EUS-B mode), aspiration for cytology and cyst fluid analysis for carcinoembryonic antigen (CEA), amylase and glucose levels; and allows to tissue sample in case of mural nodules o wall thickness. Even though EUS-FNA has been shown to be the test of choice for select lesions with high-risk features, has its limitations related to low sensitivity and specificity. The morphological characterization by EUS of PCL, as well as with the cross-sectional images, depends most of the time, on the subjective interpretation of the operator, which can be very difficult sometimes and depend on experience. A cyst fluid CEA cutoff of 192 ng/mL has been commonly accepted for differentiating mucinous from non-mucinous cysts. However, has the limitation of requiring at least 0.5 mL of cyst fluid for CEA analysis, has a relatively low sensitivity (75%) and specificity (84%), cannot differentiate cyst histotypes, and controversial results have been reported. Finally targeted cyst wall with the tip of the FNA needle can increase the diagnostic accuracy, yet the cytological yield with EUS-FNA remains low due to the relatively small tissue sample. Hence, diagno