Pancreatic Cystic Neoplasms
Pancreatic cystic neoplasms are made up of a variety of neoplasms with a wide range of malignant potential. These neoplasms are divided into serous cystadenomas, mucinous cystadenomas, and intraductal papillary mucinous neoplasms (IPMN). The latter two mucinous neoplasms carry a malignant potential. These cysts typically require differentiation from inflammatory pseudocysts. The correct diagnosis is paramount in order to institute appropriate therapy.
Differentiating these cystic neoplasms from a pseudocyst is often based on a patient's prior history of pancreatitis and risk factors for pancreatitis. Radiographically, the stigmata of pancreatitis such as diffuse calcifications or inflammatory changes surrounding the pancreas may often help in distinguishing pseudocyst from a cystic neoplasm.
Distinguishing serous cystadenomas from mucinous neoplasms (mucinous adenomas or IPMN) is also important because serous cystadenomas do not have any significant malignant potential. Radiographically, serous cystadenomas occasionally have a starburst appearance with a centrally located scar; this scar is present in approximately 30% of the patients evaluated with a CT scan. Mucinous cystadenomas often typically have multiple cystic areas with intracystic septae and may occasionally have peripheral calcifications. Furthermore, they occur almost exclusively in females. IPMN are associated with a connection to the pancreatic duct either via endoscopic retrograde cholangiopancreatography or MRCP. This distinguishes IPMN from mucinous cystic neoplasms.
Further evaluation of cystic neoplasms often includes endoscopic ultrasound with fine-needle aspiration. Analysis of cystic fluid can help in obtaining a correct diagnosis. Cyst fluid carcinoembryonic antigen (CEA) has been shown to be the most accurate for differentiating mucinous cystic neoplasms. Whereas a high CEA level (ie, > 182 ng/mL) is more indicative of a mucinous cystic neoplasm, a very low cystic fluid CEA (< 5 ng/mL) is more indicative of a serous cystadenoma.
Occasionally, it requires a combination of tests to help distinguish inflammatory pseudocysts from cystic neoplasm. A multidisciplinary approach incorporating gastroenterologists, surgeons, and radiologists is often required.
With regard to treatment, resection is typically indicated for symptomatic cystic neoplasms and those associated with a solid component or mural nodule. Most authorities agree that mucinous cystic neoplasms greater than 3 cm should also be considered for resection in the appropriate medically fit patient.