Clinical approach to incidental pancreatic cysts

Table 1 Key differences between 2012 International Association of Pancreatology and 2015 American Gastroenterological Association guidelines for the management of pancreatic cysts[10,20]

Specifics of guidelines	2012 IAP	2015 AGA
Patient population targeted by guideline	Suspected MCN and IPMN	All incidental pancreatic cysts
Recommended imaging modality	Pancreatic protocol CT or MRI	MRI pancreas with MRCP
Threshold for recommending EUS and/or surgery	1 risk factor	At least 2 risk factors
Surveillance recommendations in unresected cysts	Frequent surveillance based on cyst size	MRI in 1 yr and then every 2 yr
Stopping surveillance	No explicit recommendation to stop in unresected cysts Following resection of serous cystadenoma and MCN without invasive cancer	After 5 yr of stable unresected cyst without development of high risk features Surgically unfit patients Select resected cysts including BD-IPMN with no, low or moderate-grade dysplasia

IAP: International Association of Pancreatology; AGA: American Gastroenterological Association; MRI: Magnetic resonance imaging; EUS: Endoscopic ultrasound; MCN: Mucinous cystic neoplasm; IPMN: Intraductal papillary mucinous neoplasms; MRCP: Magnetic resonance cholangiopancreatography; CT: Computed tomography.

Table 2 Recommended cyst fluid studies[28,33,34,40]

Cyst fluid test	Test characteristics	Diagnosis
String sign ≥ 1 cm, ≥ 1 s	95% specificity, 94% positive predictive value	Mucinous
Cyst fluid cytology	63% sensitivity	Mucinous or malignant
Cyst wall cytology	29% increased diagnostic yield	Mucinous or malignant
CEA > 192 ng/mL	75% sensitivity, 84% specificity	Mucinous
CEA < 5 ng/mL	50% sensitivity, 95% specificity	Serous cystadenoma, pseudocyst, cystic neuroendocrine tumor
Amylase < 250 U/L	44% sensitivity, 98% specificity	Excludes pseudocyst

Table 3 Recommended surveillance modalities and intervals for unresected pancreatic cysts according to 2012 International Association of Pancreatology guideline[10]

Size	Modality	Interval
< 1 cm	CT/MRI	2-3 yr
1-2 cm	CT/MRI	1 yr (lengthen if no change after 2 yr)
2-3 cm	EUS, MRI	EUS in 3-6 mo, then lengthen interval thereafter alternating MRI and EUS
> 3 cm	EUS, MRI	Alternate MRI and EUS every 3-6 mo

MRI: Magnetic resonance imaging; EUS: Endoscopic ultrasound; CT: Computed tomography.