title: Periampullary Diverticula Misdiagnosed as Cystic Pancreatic Lesions: A Review of 3 Cases.
abstract: BACKGROUND
  Cystic lesions on the pancreatic head can mimic fluid-filled duodenal or periampullary diverticula. We reviewed a series of cases in which periampullary diverticula were misdiagnosed as cystic pancreatic lesions.
  
  
  METHODS
  Case 1. A Chinese woman presented to the surgical outpatient clinic for intermittent upper abdominal discomfort. Contrast-enhanced MRI of the abdomen revealed a cystic-appearing lesion in the region of the pancreatic head, which was reported as a cystic pancreatic lesion. A follow-up scan showed this lesion to be filled with fluid, gas, and debris, suggestive of a periampullary diverticulum. Review of a prior CT scan confirmed a periampullary diverticulum. Case 2. A Chinese man with a history of chronic hepatitis B infection underwent an MRI of the liver, which revealed a cystic-appearing lesion in the region of the pancreatic head, reported as a cystadenoma or pseudocyst. The patient underwent an endoscopic ultrasound. A large periampullary diverticulum was discovered but there was no pancreatic head lesion. Case 3. A Chinese woman with a history total hysterectomy and bilateral salpingo-oophorectomy for ovarian malignancy underwent an MRI of the abdomen and pelvis. A cystic-appearing lesion was found in the region of the pancreatic head, which was reported as a cystadenoma or intraductal papillary mucinous neoplasm. Follow-up magnetic resonance cholangiopancreatography showed a signal void within, suggestive of gas within a periampullary diverticulum. Review of a prior CT scan showed a periampullary diverticulum.
  
  
  CONCLUSIONS
  Periampullary diverticula, when fluid-filled, can be confused with cystic lesions in the pancreatic head. Radiologists should be aware of this potential pitfall.
authors.affiliation: Department of Radiology, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Chee Hui
authors.initials: CH
authors.lastname: Ng
authors.affiliation: Department of Radiology, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Chau Hung
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000368:Aged; D014670:Ampulla of Vater; D003951:Diagnostic Errors; D004240:Diverticulum / Q000175:diagnosis*; D004378:Duodenal Diseases / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010181:Pancreatic Cyst / Q000175:diagnosis