A 63yr old man has a CT scan. A 3cm x 4cm cystic lesion is seen within the pancreatic tail. The wall of the lesion enhances. On subsequent MRCP the lesion is shown to be high signal on T2 sequences, but there are internal low signal components within its dependant portion. What is the most likely diagnosis?
Serous Cystadenoma | |
Mucious Cystadenoma | |
IPMT (Intraductal Papillary Mucinous Neoplasm) | |
Pseudocyst | |
Adenocarcinoma |
Pancreatic pseudocysts are the most common cystic pancreatic lesion, and should always be considered in a patient with a history of pancreatitis (or the causes thereof). On CT they usually appear cystic with an enhancing wall, and can be very large. On MRI they are typically of homogenous T2 signal, and on MRI the presence of layering or dependent debris is highly specific. 50% of pseudocysts maintain a connection with the pancreatic duct and are therefore difficult to treat, as fluid can reaccumulate. Indications for treatment are infection, or mass effect from their potentially large size.
Worrying features which would point towards the other differentials are; internal septations, calcifications, central scars, a dilated pancreatic duct, solid enhancing components or an irregularly thickened wall. Mucinous cystic neoplasms (of which mucinous cystadenoma is a form) occur almost exclusively in women (99%).
References
http://radiopaedia.org/articles/pancreatic-pseudocyst-1
http://www.radiologyassistant.nl/en/p4ec7bb77267de/pancreas-cystic-lesio... - An excellent article taking you through the various cystic pancreatic lesions.