Insight into gastrointestinal heterotopic pancreas: imaging evaluation and differential diagnosis

Abstract

Heterotopic pancreas (HP) is an uncommon congenital abnormality in the developmental process of the pancreas, with gastrointestinal heterotopic pancreas (GHP) being the most common HP. The clinical manifestations of GHP may have variable patterns of presentation, dictated by both the anatomic location and the functional ability of the lesion. The most common imaging modality in detecting GHP is computed tomography (CT), while gastrointestinal barium fluoroscopy, endoscopic ultrasonography, and magnetic resonance imaging (MRI) are also applied. The density and enhancement patterns of GHP are consistent with histological classifications. GHP with a predominantly acinar tissue component manifests homogeneous and marked enhancement on CT images, whereas a predominantly ductal GHP presents heterogeneous and mild enhancement. On MRI, the appearance and signal intensity of GHP were paralleled to the normal pancreas on all sequences and were characterized by T1-weighted high signal and early marked enhancement. This article provides a comprehensive review of the histopathology, clinical manifestations, imaging features of various modalities, and differential diagnosis of GHP. It is hoped that this review will improve clinicians’ knowledge of GHP and aid in accurate preoperative diagnosis, thereby reducing the misdiagnosis rate.

Case report of retroperitoneal ectopic pancreas with adrenal adenoma

“…Pancreatic ectopic tissue composed of acinar cells, islet cells, conduit cells, etc., causes inhomogeneity in the image. Sometimes ductal structures can be seen in the upper gastrointestinal ectopic pancreas ( 1 , 4 ), but we did not find them in this retroperitoneal ectopic pancreas.…”

“…Preoperative diagnosis of the ectopic pancreas is difficult. It is usually asymptomatic, but depending on size, location, and pathological changes, it may become clinically evident ( 2 , 4 , 8 ). The most common clinical symptom of the ectopic pancreas is epigastric pain ( 3 ).…”

“…We were confident in the diagnosis of adrenal adenoma and that it would be convenient to remove the adrenal adenoma at the same time as surgery, and we decided to perform an excision of the two retroperitoneal masses. The pathological results were “retroperitoneal ectopic pancreatic” and “adrenal adenoma.” Ectopic pancreatic tissue is susceptible to the same pathological conditions that affect the in situ pancreas, including pancreatitis, pseudocyst formation, and benign and malignant tumors ( 2 , 4 ). Malignant transformation of ectopic pancreatic tissue is a rare event and a diagnostic challenge, as the clinical symptoms and radiographic features of these tumors are nonspecific ( 14 ).…”

“…Ectopic pancreas occurs in the stomach (25%–52%), duodenum (27%–36%), and jejunum (15%–17%). Less common sites of an ectopic pancreas include the ileum, esophagus, and Meckel's diverticulum, but it can occasionally occur in the mesentery, hepatobiliary system, spleen, mediastinum, lung, and umbilical foramina ( 1 , 4 ). We report a case of a retroperitoneal ectopic pancreas with ipsilateral adrenal adenoma and accessory spleen.…”

Heterotopic Pancreas in the Duodenum Diagnosed after Laparoscopic Biopsy

“…Accurate preoperative diagnosis of HP is difficult because of its location and nonspecific clinical symptoms [ 5 ]. In most cases, HP is incidentally detected in patients during endoscopy, surgery, or autopsy.…”