The management of the pancreatic cystic neoplasm: the role of the EUS in Japan.

Diagnosis of cystic lesions of the pancreas is made by clinical history taking, physical examination, blood biochemical tests and diagnostic imaging, such as transabdominal ultrasound, endoscopic ultrasound (EUS), cross-sectional imaging (computed tomography and/or magnetic resonance imaging) and endoscopic retrograde cholangiopancreatography, bearing in mind the known characteristic features of the various cystic lesions that can occur in this organ. Among others, EUS, endowed with a sharp local resolving power, has been described as a highly useful examination method, because it enables concurrent fine-needle aspiration (FNA). EUS has an important role in the differential diagnosis and tumor grading (benign, premalignant or malignant) of cystic lesions. Although the differential diagnosis of cystic lesions of the pancreas based on EUS morphology is practicable to some extent, there have also been reports showing that the diagnosis might vary with the endosonographer and that the diagnostic performance of this method for tumor grading is not necessarily high. In countries overseas, differential diagnosis and tumor grading of cystic lesions of the pancreas are actively undertaken not merely by EUS morphology, but also by cyst-fluid EUS-guided FNA (EUS-FNA) cytology and measurements of pancreatic enzymes and tumor markers, and importance is attached to EUS-FNA in the latest version of the American Society for Gastrointestinal Endoscopy Guideline and in the diagnostic strategies for cystic diseases of the pancreas. Meanwhile, the current Japanese consensus is that EUS-FNA is not recommended in cases of mucinous cystic lesions suspected as being intraductal papillary mucinous neoplasm or mucinous cystic neoplasm.