E1714. Heterotopic or Ectopic Pancreas: Review of Imaging Findings
Heterotopic or ectopic pancreas refers to pancreatic tissue that lacks both anatomic and a vascular connection with the main body of the gland. It can be found at a variety of sites throughout the gastrointestinal tract but is most commonly found at the submucosa of the gastric antrum, proximal portion of the duodenum or the jejunum. There is a male prevalence, with a male to female ratio of 3:1. Most cases, up to 85% of patients and lesions are diagnosed incidentally during the execution of other procedures and imaging studies.
Educational Goals / Teaching Points
The goals of this exhibit are to review and better understand the normal anatomy along with the imaging findings regarding normal variants of the pancreas; differentiate the imaging findings from heterotopic pancreas and other common gastrointestinal malignancies that could be interpreted as such; discuss management and recommendations regarding the monitoring and treatment of heterotopic pancreas; and highlight various cases of heterotopic pancreas.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Like many other organs in the gastrointestinal tract, the pancreas has congenital abnormalities that can fall into three different categories: fusion anomalies, migration anomalies, and duplication anomalies. Heterotopic pancreas would fall into the category of a migration anomaly. The exact embryologic basis for heterotopic pancreas is unknown, but it is widely believed that deposits of pancreatic tissue are doped into the developing gastrointestinal system in an area isolated from the main body of the pancreas. Lesions are found to be homogenous on CT images. The ill-defined lesion margins that are seen on seen on CT images are reflective of the lobular morphology of the acinar component seen in histologic specimens. On upper gastrointestinal examinations, the ectopic pancreas will appear as a smooth and broad-based lesion.
The first case of heterotopic pancreas was reported in 1729 by Schults and Bonesteel. It is a rare congenital anomaly that is usually asymptomatic and can be found in a variety of different locations. During the embryonic rotation of the foregut, small parts of the dorsal and ventral portions of the pancreas are separated while continuing to develop in ectopic locations. The most common symptoms that a patient experiences from heterotopic pancreas include nausea and vomiting (27%), ulceration (27%), epigastric pain (27%), and weight loss (18%), although it is believed that most patients do remain asymptomatic. Knowledge of the most common locations and characteristic imaging appearances is key to preventing further workup and imaging studies in a patient. A more thorough understanding and consideration of this rare congenital lesion could lead to an appropriate and proper workup when patients are found to have this incidental finding in an asymptomatic case, and an appropriate management if they are found to be symptomatic.