Endoscopic ultrasound in solid pancreatic masses--current state and review of the literature.

Some 25 years ago endoscopic ultrasound (EUS) was introduced in clinical practice for better visualization of pancreas. At the time of introduction EUS was superior to other methods in detection of pancreatic masses allowing tissue diagnosis by later introduced EUS-guided fine needle aspiration (FNA). During the time EUS was improved, electronic probes replaced mechanical probes adding ability of color Doppler, power Doppler, contrast enhanced endosonography as well as EUS elastography analysis. Meanwhile, CT technology has also experienced significant improvements raising the question whether EUS has lost ground in diagnostics of solid pancreatic masses. The aim of this review was to discuss the current evidence of clinical impact of EUS and EUS-FNA in evaluation of solid pancreatic masses with special emphasis on differentiation between benign and malignant pancreatic lesions. According to the literature, the detection of small pancreatic tumors, preoperative localization of pancreatic endocrine tumors and tissue sampling by fine-needle aspiration of pancreatic masses in cases with therapeutic consequences are considered firm indications for EUS. Cytological tissue analysis remains undisputed in differentiation benign from malignant lesions, but the question when FNA is needed is discussed. Color Doppler, power Doppler, contrast enhanced endosonography and especially elastography are also discussed as tools that are bringing additional information in evaluation of pancreatic masses, however insufficient for definitive judgment of the lesion's nature. Pancreatic cancer staging as indication for EUS is discussed controversially, inconsistent results and conflicting evidence in literature making adequate conclusion impossible. However, this indicates that at least the role of EUS is no longer undisputed in this matter. Resuming the role of EUS we can state that despite some controversies EUS is very valuable method in evaluation of solid pancreatic masses and with EUS guided FNA is nowadays by far the best method for obtaining tissue diagnosis.