Pancreatic pseudocyst with duct communication (CT)

Pancreatic pseudocysts are the most common (85% to 90%) cystic lesions of pancreas, which are encapsulated peripancreatic or remote fluid collections developing after 4 weeks of an episode of acute pancreatitis. These are called pseudocysts as cyst lining is formed of fibrous tissue and not true epithelium. Cyst contents are rich in amylase.

Causes of pancreatic pseudocysts include Acute or chronic pancreatitis (most common), pancreatic trauma and rarely iatrogenic (e.g. partial gastrectomy). In cases of acute pancreatitis with inflammatory changes and seeing fluid collection developing wall or capsule in the peri-pancreatic region in follow-up imaging, is usually diagnostic of a pseudocyst. These usually arise 4 to 6 weeks after an acute episode. Pseudocysts can be followed up if the patient is asymptomatic or the cyst is smaller than 6cm as there is a chance of spontaneous resolution in smaller cysts.¹

Complications include secondary infection, hemorrhage, rupture and mass effect on adjacent structures.¹

Above axial images of contrast CT shows a large, peripherally enhancing cystic area (green arrow) in relation to the pancreas, consistent with a pseudocyst. Yellow arrow points to the pancreatic head head and orange arrow points to the distal CBD.

 

Green arrows mark the pancreatic pseuocyst and blue arrow points to the stretched residual pancreatic parenchyma of body region.


 

Sagittal reformats showing the duct (yellow arrows) in tail region.

Sagittal MPR and Sagittal Minimum Intensity Projection, showing the PD and the pseudocyst.

A communication between the PD and the pseudocyst is demonstated in the above image. 

Cysts communicating with PD are difficult to treat and tend to recur.

Presence of internal dependent debris level is regarded as highly specific for the diagnosis of pancreatic pseudocysts in MRI ².




References:
1. Imaging Diagnosis of Cystic Pancreatic Lesions: Pseudocyst versus Nonpseudocyst
Young H. Kim, Sanjay Saini, Dushant Sahani, Peter F. Hahn, Peter R. Mueller, Yong H. Auh
Radiographics, May 2005.

2. Differentiating Pancreatic Cystic Neoplasms from Pancreatic Pseudocysts at MR Imaging: Value of Perceived Internal Debris.
Michael Macari, Myra E. Finn, Genevieve L. Bennett, Kyunghee C. Cho,
Elliot Newman, Cristina H. Hajdu, James S. Babb.
Radiology April 2009.

3. Radiopaedia.