Comparison between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes using computed tomography

Figure 1 Flowchart of patients throughout the study. CE-CT: Contrast-enhanced computed tomography; CT: Computed tomography; PDAC: Pancreatic ductal adenocarcinoma; SPN: Solid pseudopapillary neoplasms.

Figure 2 Computed tomography images of two cases with solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes. A: Plain phase computed tomography images showed a hypodensity tumor with a well-defined margin, and calcifications (arrow) were observed within the tumor; B-D: The tumor showed a heterogeneous enhancement pattern in the arterial, portal venous, and delayed phases. Notably, the solid components within the tumor showed enhanced patchy-like structures, which were defined as “floating cloud sign” (arrowhead); E: Plain phase computed tomography images showed a hypodensity tumor with an ill-defined margin (arrow); F: The tumor showed a heterogeneous enhancement pattern with blood vessels wrapped by the tumor in the arterial phase; G and H: The solid components within the tumor showed a slight persistent enhancement pattern. SPN: Solid pseudopapillary neoplasms of the pancreas; PDAC: Pancreatic ductal adenocarcinoma.

Figure 3 Computed tomography images of two cases with solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes. A: Plain phase computed tomography images showed a hypodensity tumor with an ill-defined margin; B: The tumor showed a heterogeneous enhancement pattern in the arterial phase; C and D: Portal venous and delayed phases showed slight upstream pancreatic duct dilatation; E: Plain phase computed tomography images showed a hypodensity tumor with a well-defined margin (arrow); F-H: The tumor showed a heterogeneous enhancement pattern in the arterial, portal venous, and delayed phases with blood vessels wrapped by the tumor. The solid components within the tumor showed enhanced patchy-like structures with a slight persistent enhancement pattern, which were defined as “floating cloud sign” (arrowhead) (G and H). SPN: Solid pseudopapillary neoplasms of the pancreas; PDAC: Pancreatic ductal adenocarcinoma.

Figure 4  Diagnostic performance of the computed tomography characteristics and their combination (named as “model”) in differentiating pancreatic ductal adenocarcinoma with cystic changes from solid pseudopapillary neoplasms of the pancreas.