Mucinous cystic neoplasms and serous cystadenomas arising in the body-tail of the pancreas: MR imaging characterization.

PURPOSE: To identify magnetic resonance (MR)/MR cholangiopancreatography (MRCP) imaging signs helpful in the differential diagnosis between serous cystadenomas (SCAs) and mucinous cystic neoplasms (MCNs), arising from the body/tail of the pancreas.

MATERIAL AND METHODS: This retrospective study had institutional review board approval and informed consent was waived. Fifty-three patients with non-communicating cystic pancreatic neoplasm of the body/tail, undergoing MR/MRCP, were included. Qualitative image analysis assessed the macroscopic pattern, number of cysts, presence of central scar, contrast enhancement of peripheral wall, and mural nodules. Quantitative analysis assessed the maximum diameter of the neoplasm, thickness of the peripheral wall, and calibre of the upstream main pancreatic duct.

RESULTS: Histopathology results revealed that 27/53 (51 %) were SCAs, 26/53 (49 %) were MCNs. Microcystic pattern was observed in 88.2 % of SCAs and 11.8 % of MCNs; macrocystic pattern was observed in 90.5 % of MCNs and 9.5 % of SCAs (p < 0.0001). Central scar was detected in 29.6 % of SCAs and no MCNs (p = 0.003). Contrast enhancement of the peripheral wall was evident in 99.5 % of MCNs and 11.5 % of SCAs (p < 0.0001); mural nodules were depicted in 94.1 % of MCNs and 5.9 % of SCAs (p < 0.0001). Median maximum diameter was 54 mm for MCNs, 32 mm for SCAs (p = 0.001); median wall thickness was 4 mm for MCNs, 2 mm for SCAs (p < 0.0001).

CONCLUSIONS: Macrocystic pattern, enhancement of a peripheral wall and mural nodules are suggestive of MCNs; whereas microcystic pattern, lack of peripheral wall and central scar are suggestive of SCAs.

KEY POINTS: • MCNs have macrocystic patterns, contrast enhancement of the peripheral wall and mural nodules • Microcystic pattern and central scar are suggestive of SCA • Mural nodules detected in MCNs correlate with epithelial dysplasia • Chronic obstructive pancreatitis is equally depicted in patients with MCNs and SCAs.