Endoscopic Ultrasound-Fine Needle Aspiration versus Core Biopsy for the Diagnosis of Subepithelial Tumors.

Subepithelial lesions are frequently encountered and remain a diagnostic challenge. Imaging of subepithelial lesions using endoscopic ultrasound (EUS) can be helpful in narrowing the differential diagnosis of the lesion; however, definitive diagnosis typically requires tissue. Many methods for acquiring tissue exist including EUS-guided fine needle aspiration, Trucut biopsy, and fine needle biopsy. Obtaining adequate tissue is important for cytologic and histologic exams including immunohistochemical stains, thus a great deal of effort has been made to increase tissue acquisition in order to improve diagnostic yield in subepithelial lesions.