Endoscopic ultrasound-guided tissue acquisition of subepithelial masses

Difficult to diagnose on routine endoscopy, subepithelial masses typically require further investigation given their potential for malignancy. Endoscopic ultrasound has become an indispensable addition to the clinical algorithm; however, tissue sampling may still be necessary to provide an accurate diagnosis. Several modalities and variations within each modality exist for endoscopic tissue acquisition. While bite-on-bite techniques have traditionally produced disappointing results, newer techniques may improve clinical use. Fine-needle aspiration, currently recognized as the standard bearer, is plagued by modest diagnostic yields in randomized studies. Similar to fine-needle aspiration in technique, fine-needle biopsy is emerging as safe and successful with the introduction of improved needle technology. Additionally, new and exciting endoscopic techniques such as submucosal tunneling may change the paradigm of subepithelial management in the future. The following article will discuss techniques specific to endoscopic ultrasound-guided tissue acquisition.