[Endoscopic ultrasound-guided biopsy: diagnostic yield, pitfalls, quality management]

The differential diagnosis of tumorous lesions in the pancreas, liver, adrenal gland or lymph nodes is ambiguous. Specific tissue diagnoses are essential for treatment decisions. Endoscopic ultrasound-guided biopsy has proven to be a reliable and effective modality in obtaining samples for cytological or histological examinations either primarily or in cases in which other biopsy techniques have failed. The reproducibility of cytopathological diagnoses among pathologists with special experience in assessing material obtained by endoscopic ultrasound-guided biopsies is very high. False positive diagnoses of malignancy in endoscopic ultrasound-guided biopsy are rare; false negative diagnoses appear in a variable frequency depending on target tissue, technical factors, and expertise of the endosonographer and cytopathologist. There are numerous challenges and pitfalls in the differential diagnostic classification of benign and malignant lesions. These problems are related to the characteristics of samples obtained by endoscopic ultrasound-guided biopsy, as well as to the multiple diagnoses with similar or overlapping cytological or histological characteristics. This review discusses the performance of endoscopic ultrasound-guided biopsy in establishing specific tissue diagnoses, possible pitfalls as well as opportunities to minimise differential diagnostic errors.