Endoscopic ultrasound-guided fine-needle aspiration biopsy for the diagnosis of gastrointestinal submucosal tumors

Gastrointestinal submucosal tumors (SMT) detected by barium meal study or endoscopy include various kinds of diseases and various degrees of malignancy. Endoscopic ultrasonography (EUS) can provide useful information about the differentiation of intra- and extra-wall lesions, location and originating layer, presumption of their histological nature, measurement of the actual size of the lesion, and the possibility of differentiating between a benign and a malignant lesion. However, EUS alone does not reveal the complete pathology. EUS fine-needle aspiration biopsy (EUS-FNAB) has been reported to be a useful tissue sampling method for pancreatic mass lesions, lymph nodes swelling, posterior mediastinal masses and also gastrointestinal submucosal tumors. The EUS-FNAB procedure is effective not only for the differential diagnosis of benignancy and malignancy, but also for the specific histopathological nature of gastrointestinal SMT using immunohistochemical staining. When used with MIB-1 (Ki-67) staining, and gene analysis in case of gastrointestinal stromal tumor, EUS-FNAB may indicate its prognosis and influence decisions regarding therapeutic strategy. Thus, EUS-FNAB is an indispensable procedure in the diagnosis of SMT.