Macrocystic pancreatic lesions: Differentiation of benign from premalignant and malignant cysts by CT

Abstract

Objective To assess useful CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions. Methods Seventy-four patients with pathologically proven macrocystic pancreatic lesions were enrolled: 17 benign cysts (macrocystic serous cystadenoma, n = 12; congenital cyst; n = 5) and 57 premalignant and malignant cysts (mucinous cystic neoplasm, n = 28; intraductal papillary mucinous neoplasm of branch duct type, n = 20; tumor with cystic change, n = 9). Size, location, shape (lobulated, round or oval, or complex cystic with tubular cyst), wall thickness (thin, ≤1 mm; thick, >1 mm), internal surface (smooth or irregular), and other findings were analyzed with multiphasic CT with thin-section (2.5–3 mm) images. CT features between two groups were compared using univariate and multivariate stepwise logistic regression analyses. Results On univariate analysis, the differences for the shape ( p = 0.007), wall thickness ( p = 0.011), and internal surface ( p = 0.012) between benign and premalignant and malignant cysts were significant. A lobulated shape, a thin wall and a smooth internal surface were more frequent in benign cysts, whereas a round or oval shape or a complex cystic shape with tubular cyst, a thick wall and an irregular internal surface were more frequent in premalignant and malignant cysts. On multivariate analysis, the shape ( p = 0.002) and wall thickness ( p = 0.025) were significant CT features for differentiating benign from premalignant and malignant cysts. Conclusion Shape and wall thickness are the main CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions.