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

Table 1 Comparisons of the clinical and imaging findings between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes

Variables	SPN, n = 32	PDAC with cystic changes, n = 14	P value
Sex
Male	8 (25)	7 (50)	0.170
Female	24 (75)	7 (50)
Age in yr	32.00 ± 13.04	64.93 ± 11.72	< 0.001
Location
Head & neck	14 (43.75)	9 (64.3)	0.337
Body & tail	18 (56.25)	5 (35.7)
Shape
Round	12 (37.5)	1 (7.1)	0.072
Lobulated or irregular	20 (62.5)	13 (92.9)
Margin
Well-defined	21 (65.6)	5 (35.7)	0.060
Ill-defined	11 (34.4)	9 (64.3)
Density
Predominantly solid	2 (6.25)	0 (0)	0.384
Cystic-solid	28 (87.50)	14 (100)
Predominantly cystic	2 (6.25)	0 (0)
Calcification
Yes	11 (34.4)	1 (7.1)	0.073
No	21 (65.6)	13 (92.9)
“Floating cloud” sign
Yes	27 (84.4)	6 (42.9)	< 0.001
No	5 (15.6)	8 (57.1)
Pancreatic atrophy
Yes	6 (18.75)	5 (35.7)	0.269
No	26 (81.25)	9 (64.3)
MPD dilatation
Yes	12 (37.5)	9 (64.3)	0.117
No	20 (62.5)	5 (35.7)
Peripancreatic invasion or distal metastasis			0.006
Yes	2 (6.25)	6 (42.9)
No	30 (93.75)	8 (57.1)
Enhancement pattern			0.504
Homogeneous	1 (3.1)	0 (0)
Heterogeneous	31 (96.9)	14 (100)
Size in cm	5.41 ± 2.89	3.90 ± 1.24	0.017
CT attenuation values in HU
Plain phase	37.37 ± 4.82	36.82 ± 4.80	0.729
Arterial phase	55.39 ± 7.57	54.88 ± 10.85	0.854
Portal venous phase	66.79 ± 7.31	67.99 ± 13.03	0.691
Delayed phase	73.34 ± 7.16	72.70 ± 9.47	0.799
Tumor-to-pancreas enhancement ratio
Arterial phase	0.57 ± 0.10	0.61 ± 0.11	0.224
Portal venous phase	0.67 ± 0.11	0.66 ± 0.13	0.833
Delayed phase	0.81 ± 0.08	0.79 ± 0.09	0.557

Data are n (%). CT: Computed tomography; HU: Hounsfield unit; MPD: Main pancreatic duct; PDAC: Pancreatic ductal adenocarcinoma; SPN: Solid pseudopapillary neoplasms.

Table 2 Diagnostic performance of computed tomography characteristics and their combination (named as “model”) in differentiating pancreatic ductal adenocarcinoma with cystic changes from solid pseudopapillary neoplasms

Variables	AUC	Sensitivity, %	Specificity, %	Accuracy, %	PPV, %	NPV, %
Tumor size	0.634	79	53	61	42	85
“Floating cloud” sign	0.708	57	84	76	62	82
Peripancreatic invasion or distal metastasis	0.683	43	94	78	75	79
Model	0.833	79	81	80	65	90

AUC: Area under curve; NPV: Negative predictive value; PPV: Positive predictive value.