Current indications and yield of endoscopic ultrasound and ancillary techniques in pancreatic cystic neoplasms

Diagnostic value of EUS-guided SF6 pancreatography for pancreatic cystic lesions on cyst communication with the pancreatic duct

Background and Objectives

ERCP remains the reliable method to determine whether pancreatic cystic lesions (PCLs) and pancreatic duct communicate when other modalities (computed tomography, magnetic resonance imaging, and EUS) fail. However, complications after ERCP are still a risk that should not be ignored. In this study, we evaluated the value of EUS-guided SF6 pancreatography (ESP) for the diagnosis of PCLs focusing on pancreatic cyst communication with the pancreatic duct.

Patients and Methods

We reviewed the database of medical records to retrieve the clinicopathological data of the patients with PCLs who had undergone ESP, and analyzed the diagnostic value of ESP to determine communication between the cyst and the pancreatic duct. The inclusion criteria were as follows: (1) PCLs were pathologically diagnosed by postsurgery specimen or through-the-needle biopsy and (2) ESP was performed to determine communication between the pancreatic cyst and the pancreatic duct.

Results

Pathological diagnosis confirmed communication with the pancreatic duct in all eight patients with positive pancreatography, among whom seven were branch-duct-intraductal papillary mucinous neoplasm (BD-IPMN) and one was the main duct-IPMN. Pathological diagnosis confirmed noncommunication with the pancreatic duct in 20 of the 21 patients with negative pancreatography, among whom 11 were mucinous cystic neoplasm, 7 were serous cystic neoplasm, 1 was solid pseudopapillary neoplasm, 1 was pancreatic pseudocyst, and 1 was BD-IPMN. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of ESP to determine communication between the pancreatic cyst and the pancreatic duct were 96.6% (28/29), 88.9% (8/9), 100% (20/20), 100% (8/8), and 95.2% (20/21), respectively.

Conclusions

ESP achieved high accuracy to determine communication between the pancreatic cyst and the pancreatic duct.

Advances in the Diagnosis of Pancreatic Cystic Lesions

Pancreatic cystic lesions (PCLs) are a heterogenous group of lesions ranging from benign to malignant. There has been an increase in PCLs prevalence in recent years, mostly due to advances in imaging techniques, increased awareness of their existence and population aging. Reliable discrimination between neoplastic and non-neoplastic cystic lesions is paramount to ensuring adequate treatment and follow-up. Although conventional diagnostic techniques such as ultrasound (US), magnetic resonance imaging (MRI) and computer tomography (CT) can easily identify these lesions, assessing the risk of malignancy is limited. Endoscopic ultrasound (EUS) is superior to cross-sectional imaging in identifying potentially malignant lesions due to its high resolution and better imaging characteristics, and the advantage of allowing for cyst fluid sampling via fine-needle aspiration (FNA). More complex testing, such as cytological and histopathological analysis and biochemical and molecular testing of the aspirated fluid, can ensure an accurate diagnosis.

Pancreatic Cysts: Diagnostic Role of EUS-Guided Microforceps Biopsy and Confocal Laser Endomicroscopy

Frequent use of high-quality cross-sectional imaging has led to a significant rise in diagnosis of pancreatic cystic lesions (PCLs). Despite the fact that enormous effort has been put into the research of PCLs within the last two decades and multiple guidelines have been developed, our clinical decision-making especially in regard to mucinous lesions remains limited. Currently, clinical assessment, cross-sectional imaging and EUS with fluid analysis (if appropriate) belong to the standard care in patients with PCLs. For differentiation of mucinous from nonmucinous cysts, the sensitivity of cytological investigation and CEA in the cyst fluid is 42% and 52-79%, respectively. Due to the limited accuracy, further diagnostic tools are warranted. Two EUS-guided approaches have been introduced recently. Through-the-(19-gauge EUS) needle Moray microforceps have been developed, and several studies have acknowledged their contribution to the correct diagnosis as they help to overcome limited cellularity of the EUS-guided cyst fluid aspiration and traditional cytology. Confocal laser endomicroscopy offers real-time images and seems to be a promising method for the diagnosis and differential diagnosis of pancreatic PCLs. Example images of the needle-based confocal laser endomicroscopy criteria for the diagnosis of PCLs have been suggested recently. Before both, Moray microforceps and confocal laser endomicroscopy can be widely accepted, further studies are necessary to determine the real diagnostic yield and the clinical efficacy.