Retroperitoneal pseudocyst dissecting into the pleural space

Case contributed by Michael P Hartung


History of chronic pancreatitis due to alcohol abuse. Persistent left upper abdominal pain.

Patient Data

Age: 55 years
Gender: Male

Small to medium left pleural effusion. Circumferential thickening of the distal esophagus with hazy surrounding soft tissue extending into the retroperitoneum toward the pancreatic tail. Small peripherally enhancing fluid collection along the posterior gastric body, with ill-defined soft tissue thickening along the lesser curvature. Findings of chronic calcific pancreatitis with multiple parenchymal and ductal calcifications. Mild pancreatic ductal dilatation. 

Similar dilatation of the main pancreatic duct, 4 mm. Similar small peripheral enhancing T2 hyperintense collections along the pancreatic tail likely reflecting small pseudocysts, with a larger collection extending to the posterior gastric fundus, measuring 1.1 x 0.7 cm. 

A serpentine peripherally enhancing, T2 hyperintense collection ascends along the medial aspect of the pancreatic tail through retroperitoneum and diaphragmatic crura and communicates with the left pleural space. Pleural thickening/enhancement is present. This collection has a maximum axial dimension of 1.6 x 1.5 cm and measures approximately 7 cm in length.

Case Discussion

The retroperitoneal pseudocyst is particularly difficult to see on the CT, however, there is the suggestion of some degree of inflammation tracking up from the pancreas evidence by retroperitoneal stranding, esophageal wall thickening/hazy surrounding soft tissue, and left pleural effusion.

On the MRI, a thin, serpentine enhancing tract of fluid can be seen extending from the pancreatic tail through the diaphragm and into the left pleural space, resulting in pleural effusion and pleural enhancement. In particular, the T2 fat sat and postcontrast sequences show the pseudocyst most effectively. This inflammatory pleural effusion is likely responsible for the patient's persistent left upper quadrant pain. There is also a small, chronic gastric subserosal pseudocyst along the posterior body.

Pseudocysts are most commonly thought of as surrounding the pancreas. However, over time they can track basically anywhere along the path of least resistance: Inferiorly into the pelvis or superiorly into the mediastinum and even into the neck.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.