Approach to Diagnosis and Management of Pancreatic Cystic Lesions
With the widespread use of cross-sectional imaging, the frequency of incidentally
diagnosed pancreatic cystic lesions continues to increase in 2.6%–37.6%. It is very
important to distinguish the different type of pancreatic cystic tumors with varied
prognosis and therapies. Mucinous varieties (mucinous cystic neoplasms and
intraductal papillary mucinous tumors) are premalignant or malignant and surgical
resection is generally recommended. Nonmucinous varieties are with very low
malignant potential (serous cystadenomas) and always benign (pseudocysts).
EUS has been widely used for diagnosis and treatment of pancreatic lesions. To diagnosis the pancreatic cystic lesions, EUS provides image evaluation, cystic fluid analysis and tissue acquisition. Imaging evaluation of pancreatic cystic tumors with EUS includes pancreatic parenchyma (evidence of chronic pancreatitis), ductal structures, cyst wall thickness, protrusions, cyst contents (debris, mucin) and others (liver metastasis, enlarged lymph nodes, ascites and vessels). Contrast enhanced EUS has been introduced for image evaluation of pancreatic lesions.
However, EUS morphology alone for differentiating between mucinous and nonmucinous cystic lesions has been reported with poor overall accuracy. Therefore, EUS-guided sampling has been suggested to increase the diagnostic yield. There were guidelines indicating the indication of EUS-FNA for pancreatic cystic lesions. The EUS guided sampling includes fluid aspiration/analysis and EUS-guided tissue acquisition. The diagnostic accuracy is low with cytological analysis alone, and may be increased with checking the biochemical levels and tumor marker (CEA). EUS guided cystic wall aspiration is with lower accuracy compared with EUS guided TTNB. EUS-TTBN can be done with microforceps. The liquid biopsy is another potential diagnostic tool.
The treatment of pancreatic cystic lesions is indicated for ones with pre-malignant /malignant component or causing symptoms. EUS-guided ablation included ethanol with/without oncological agents and FRA.
EUS provides less invasive method for tissue diagnosis and treatment of pancreatic cystic lesions