1. Solid Pseudopapillary Tumor of the Pancreas: Diagnosis with CT and MRI
Mengsu Zeng, Xiuzhong Yao
曾蒙苏 姚秀忠
Department of Radiology, Zhongshan Hospital of Fudan University and Department of Medical Image, Shanghai Medical College of Fudan university, Shanghai, China

2. Background
With the increasing radiological reports of Solid pseudopapillary tumor of the pancreas, its typical imaging features have been well known to radiologists.
However, with the improvement in the imaging modalities and widespread use of CT and MRI, those atypical neoplasms have been becoming more and more common.

3. SOLID-PSEUDOPAPILLARY EPITHELIAL NEOPLASM
肿瘤实质和囊性成分
年轻女性 (35岁) 85%
边缘包膜清晰，境界规则
周缘或中心可见钙化（ 29% of 56 pts）
Buetow, et al. Radiology 1996; 199:707
肿瘤位于胰腺体尾部较多见
手术切除预后好
（恶性程度与肿瘤大小、年龄正比）
李卉 曾蒙苏 等 中华放射学 2006，8：846
史讯 曾蒙苏 等 放射学实践 2007，11：356
史讯 曾蒙苏 等 中国医学计算机成像2007，13；370
姚秀忠 曾蒙苏等 中国肿瘤影像学杂志2010，5；458
中山医院
门诊大楼

5. The purpose of this study was to
investigate the accuracy of CT
and MRI for diagnosis of solid
pseudopapillary tumor of the pancreas
(SPTP).

6. Material and Methods 39 patients with SPTP proven by histopathology
were divided into the correct diagnosis and
misdiagnosis group based on the preoperative
imaging and histopathologic results.
All CT and MR imaging signs, including gender,
age, tumor size, modalities (CT or MRI), location,
shape, capsule, cystic degeneration, hemorrhage,
calcification and enhancement type, were
retrospectively evaluated with a correlation to their
pathologic findings and statistically analyzed.

7. Results Among 39 imaging cases,
15 (38.5%) misdiagnosed (mean age years old)
24(61.5%) diagnosed. (mean age years old, p=0.000).
Tumor size tended to be smaller in the elder group and had a negative linear correlation with the patient age (r=-0.408, p=0.025).
cause of higher misdiagnosis: correctly diagnosis :
the older patients (p=0.007), gender,
small tumors (p=0.037), location,
CT (p=0.049) shape,
non-hemorrhage (p=0.000) capsule,
cystic degeneration,
calcification
type of enhancement .
Macroscopically, large SPTPs were more likely to appear the capsule (p=0.002),
cystic degeneration (p=0.003)
and hemorrhage (p=0.029) than small tumors.

8. Results N Mean (cm) P value size misdiagnosis 15 5.0000 0.289 24
Table 1 Comparison of tumor size and age between two groups N
Mean (cm)
P value
size
misdiagnosis 15
5.0000
0.289
Correct diagnosis 24
6.1167
age
0.000

9. Results
Graph 1 Linear regression analysis of tumor size and patient age
Note: Bconstant=7.435, p=0.000; Bage=-0.067, p=0.025

10. Table 2 imaging Analysis
Evaluations
correct diagnosis
misdiagnosis
Misdiagnosis Rate
P value
Gender
Male 3
50.0%
Female 21 12
36.4%
0.658
Age＊
The elder(≥40) 5 10
66.7%
The younger(＜40) 19
22.8%
0.007
Size＊
Large (＞3.0cm) 22 9
29.0%
Small (≤3.0cm) 2 6
75.0%
0.037
Modalities＊ CT 11
52.2%
MRI 13
38.5%
0.049
Location
Head 7
46.2%
Body
40.0%
Tail 8
2.3%
0.631
Shape
Round
38.9%
Oval 4
33.3%
Lobulated
44.4%
0.873
Capsule
Presence 20
28.6%
Absence
63.6%
0.068
Cystic degeneration 17
32.0%
50%
0.318
hemorrhage＊ 1
8.3% 14
51.9%
0.013
calcification
35.5%
0.686
gradual enhancement
37.5%
1.000
Table 2 imaging Analysis
of SPTP between
Two groups

11. Results Table 3 Tumors’ demonstrations between CT and MRI Findings CT
P value
Capsule
Presence 14
Absence 9 2
0.086
Cystic degeneration 12 13 11 3
0.093
hemorrhage 1 22 5
0.000
calcification 8 15
0.028
gradual enhancement 21
0.547

12. Table 4 Histopathological analysis in tumor size and patient age
Results
Table 4 Histopathological analysis in tumor size and patient age
Findings
Size Group
P value
Age Group
Large
Small
The elder
The younger
Capsule
Presence 23 1 7 17
Absence 3 5
0.002
0.116
Cystic degeneration 22 6 4
0.003
0.049
hemorrhage 18 14 8
0.029
0.150
calcification 2
1.000

13. Fig. 1.—23-year-old woman with a typical solid pseudopapillary tumor of pancreas
Fig. 1a
(a) Photograph of gross surgical specimen demonstrates the fibrous capsule, hemorrhagic areas and cystic degeneration.

14. Fig. 1b
Fig. 1c
Fig. 1.—23-year-old woman with a typical solid pseudopapillary tumor of pancreas
(b, c) T2 weighted image and T1 weighted image with fat suppression showed the typical imaging features: the capsule, cystic degeneration and hemorrhagic areas.

15. Fig. 1e
Fig. 1d
(d, e,f) Dynamic contrast-enhanced MR scans revealed the early peripheral enhancement with progressively fill in and delayed enhancement of the capsule.
Fig. 1f

16. Fig. 2.—19-year-old woman with a solid pseudopapillary tumor of pancreas misdiagnosed as mucinous cystic adenocarcinoma.
Fig. 2a
(a) Photograph of gross surgical specimen demonstrated the septations among chamberlets with cystic degeneration and the incomplete pseudocapsule.

17. Fig. 2b
Fig. 2c
(b, c,d) Dynamic contrast-enhanced CT scans demonstrated the pseudoseptate type enhancement and contrast medium was progressively filled in from the septation and margin to the centre of tumors.
Fig. 2d

18. Fig. 3 —51-year-old man with a small solid pseudopapillary tumor of pancreas.
Fig. 3a
(a) Photograph of gross surgical specimen demonstrated a small solid tumor with the thick and irregular rim.

19. Fig. 3b
Fig. 3c
(b) Axial T1-weighted image reveals the tumor’s rim with hyperintense and the solid portions with homogeneous hypointense.
(c, d) The small tumor appeared imperceptible in the contrast-enhanced T1-weighted and CT images on the delayed phase.
Fig. 3d

20. Fig. 4—49-year-old woman with a solid pseudopapillary tumor of pancreas misdiagnosed as an inflammatory mass.
Fig. 4a
(a) Photograph of gross surgical specimen demonstrated a relatively large solid tumor without pseudocapsule and hemorrhagic areas.

21. (b) Axial unenhanced CT showed
Fig. 4c
Fig. 4b
(b) Axial unenhanced CT showed
the swelling pancreatic head with isodensity.
(c, d), Dynamic contrast-enhanced CT scans displayed a large tumor with markedly early and delayed enhancement in the pancreatic head.
Fig. 4d

22. Conclusion
To avoid misdiagnosis, it should be very careful to evaluate some characteristic imaging signs in small tumors and those occurred to the aged. Compared to CT, MR was much superior to avoid misdiagnosis of SPTP.