Preoperative diagnosis of
pancreatic cysts benefits from integrating the clinical, radiological, and cytological features. As patient management algorithms evolve to increasingly nonsurgical options, accuracy in distinguishing mucinous from nonmucinous and benign from malignant mucinous
cysts is important. This review focuses on pseudocysts,
serous cystadenomas, intraductal papillary
mucinous neoplasms (IPMNs), and mucinous
cystic neoplasms. Patients with pseudocysts almost always present with
pancreatitis and are usually medically managed. Radiological studies reveal a unilocular
cyst mostly in the pancreatic tail. Cyst fluid is thin, with high
amylase but low
carcinoembryonic antigen (CEA) levels.
DNA mutations are absent.
Serous cystadenomas are benign and do not require resection. Patients are usually asymptomatic and have microcystic or macrocystic masses anywhere in the pancreas. Cytology is frequently nondiagnostic. CEA and
amylase levels are low.
DNA analysis may reveal loss of heterozygosity (LOH) at 3p if associated with
Von Hippel-Lindau disease. Neoplastic mucinous
cysts are highly variable in their presentation. Most are resected. Mucinous
cystic neoplasms typically arise in the body or tail of the pancreas of middle-aged women and demonstrate a septated
cyst without dilatation of the main pancreatic duct. Branch duct IPMNs are more common in the pancreatic head of elderly men. Main duct dilatation correlates with main duct or combined type IPMN. Both types of mucinous
cysts produce variable amounts of
mucin. Cytologically nonmalignant but atypical epithelial cells, even when scant, are an indication of a high risk for
malignancy. High CEA level supports a mucinous
cyst, as do KRAS mutation and good quality
DNA levels. KRAS mutation and multiple LOH support
malignancy.