What are the characteristic features of the four major cystic pancreatic neoplasms?
A. Serous cyst adenoma (SCA) is more common in women older than 60, is overwhelmingly benign, and is often in the pancreatic head. SCA is composed of numerous cysts smaller than 2 cm. It calcifies more commonly than other pancreatic tumors.
US: Often appears solid and hyperechoic because of multiple small cysts that may not be individually resolved. A hyperechoic central stellate scar and calcifications suggest the diagnosis.
MDCT: Innumerable minute cysts may appear solid, whereas multiple small but visible cysts may have a honeycomb or “Swiss-cheese” appearance. A central stellate scar and calcifications suggest the diagnosis.
B. Mucinous cystic neoplasms
a. Female predominance (9:1)
b. Patients 40 to 60 years old
c. Strong predilection for the pancreatic tail (85%)
d. Peripherally calcify in 10% to 25% of cases
e. Considered malignant
f. Larger than 5 cm in diameter
g. Composed of unilocular or multilocular cysts larger than 2 cm
US: Better depicts solid excrescences and internal septations of variable number and thickness; usually thicker than septations in SCA tumors.
MDCT: Better demonstrates tumor wall and organ of origin.
C. Intraductal papillary mucinous tumors (IPMT) are rare but are most prevalent in men older than 60 years of age. They produce large amounts of mucin, which can result in ductal dilatation caused by mucin plugs. ERCP is best for diagnosis. IPMTs are usually (40%-80%) malignant. Findings associated with malignancy include (1) ductal dilatation larger than 10 mm, (2) large mural nodules, (3) intraductal calcifications, (4) bulging duodenal papilla, and (5) diffuse or multifocal involvement. Intraductal papillary nodules and a prominent duodenal papilla can distinguish this tumor from chronic pancreatitis.
D. Solid pseudopapillary tumor of the pancreas is most often seen in younger (≈ 25-year-old) black or Asian women and is characteristically present in the pancreatic tail. They are often large (9 cm) at presentation and have a low malignant potential. On CT, fluid-debris levels can be present because of hemorrhage.