Cystic masses of the pancreas.

Although the pseudocyst is the most common cystic mass of the pancreas found at imaging studies, radiologists should be aware of the multiple disease processes that can manifest in a similar manner. This article reviews these other entities by category of the origin of the mass, including congenital, inflammatory, and neoplastic. Computed tomography, ultrasound, and magnetic resonance imaging studies are presented, and, although the considerable overlap of imaging features makes it generally impossible to render a specific diagnosis, combining the findings from these modalities is helpful in formulating a differential diagnosis. Because a cystic mass of the pancreas is not always a pseudocyst, percutaneous drainage should be followed by cytologic analysis of the aspirate. A biopsy of the wall of the cystic mass may also be necessary.