Feasibility of Intratumoral Confocal Microscopy under Endoscopic Ultrasound Guidance

The primary goal of this study was to develop descriptive image interpretation criteria and a classification of endoscopic ultrasound-confocal microscopy (EUS-CM) findings in pancreatic masses and lymph nodes through a review of prospectively obtainedEUS-CM videos from proven malignant and benign cases, and to propose diagnostic criteria for predicting malignancy. The materialused was a 19-G EUS-needle in which the stylet was replaced by the confocal mini-probe. The mini-probe pre-loaded in the EUSneedlewas guided endosonographically in the target then the mini-probe was pushed under EUS guidance into the lesion. Elevenpatients mean age 62.3 years underwent EUS for the staging of a pancreatic mass (3 cystic and 4 solid) or for the diagnosis of celiacand/or mediastinal LN (n = 4). Benign intraductal papillary mucinous neoplasm (IPMN) was characterized by the aspect of fingerlikeprojections which correspond to the villous changes of intestinal IPMN type. In pancreatic adenocarcinomas, EUS-CM foundvascular leakage with irregular vessels with leakage of fluorescein into the tumor, large dark clumps which correspond to humps ofmalignant cells. Inflammatory lymph nodes were characterized by the presence of diffuse small cells into a homogeneous stromawith a normal vascularization. At the opposite, EUS-CM showed in malignant lymph node glandular structures with dark cells, largedark clumps and an important neo-vascularization with huge leakage of fluorescein.