ARRS Case of the Week


Case Author: Ramit Lamba, MBBS, MD, University of California, Davis


45-year-old woman with finding of asymptomatic calcification in the left upper quadrant on a chest radiograph obtained as part of an employment health screening.

Imaging Findings

Axial (A) and sagittal (B) CT images though the upper abdomen show a cystic encapsulated mass in the left upper quadrant originating from the pancreatic tail. Calcifications are present in the outer cyst wall. Axial T2-weighted MR image (C) through the lesion confirms its cystic encapsulated nature. Axial unenhanced (D) and gadolinium-enhanced (E) T1-weighted fat-suppressed MR images confirm the presence of the nonenhancing cystic mass in the pancreatic tail. A focal nonenhancing area of increased signal intensity (arrowhead) likely represents focal hemorrhage.

  • Congenital true cyst (lymphoepithelial cyst)
  • Hydatid cyst
  • Mucinous cystic neoplasm
  • Pancreatic pseudocyst
  • Serous oligocystic adenoma


Serous oligocystic adenoma

Teaching Points

Oligocystic variants of microcystic serous tumors have fewer than 6 cysts (commonly a single cyst) and a cyst size greater than 2 cm. Oligocystic variants are being recognized with greater frequency and account for as many as 25% of serous tumors. Thus the differential diagnosis of a macrocyst in the pancreas includes serous oligocystic tumor. On images, serous oligocystic adenoma can mimic a mucinous tumor. Preoperative differentiation of these two diagnoses with endoscopic ultrasound- or CT-guided cyst aspiration should be performed because mucinous tumors have malignant potential. Cyst fluid in serous tumors typically has low viscosity, a low carcinoembryonic antigen (CEA) concentration, and normal results of DNA analysis. These findings contrast to the viscous nature of the mucinous fluid, high CEA concentration, and often abnormal results of DNA analysis of mucinous tumors. Serous cystic tumors of the pancreas are almost always benign. Resection is recommended for larger tumors (> 4 cm) because they can obstruct the pancreatic and bile ducts and cause pancreatic parenchymal atrophy.

Suggested Readings

Choi JY, Kim MJ, Lee JY, et al. Typical and atypical manifestations of serous cystadenoma of the pancreas: imaging findings with pathologic correlation. AJR 2009; 193:136–142
Khurana B, Mortelé KJ, Glickman J, Silverman SG, Ros PR. Macrocystic serous adenoma of the pancreas: radiologicpathologic correlation. AJR 2003; 181:119–123

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