复旦大学附属中山医院 Zhongshan Hospital Fudan University

Solid Pseudopapillary Tumor of the PancSolid Pseudopapillary Tumor of the Pancreas: Diagnosis with CT and MRIreas: Diagnosis with CT and MRI

Mengsu Zeng, Xiuzhong YaoMengsu Zeng, Xiuzhong Yao曾蒙苏 姚秀忠曾蒙苏 姚秀忠

Department of Radiology, Zhongshan Hospital oDepartment of Radiology, Zhongshan Hospital of Fudan University and Department of Medical If Fudan University and Department of Medical I

mage, Shanghai Medical College of Fudan univermage, Shanghai Medical College of Fudan university, Shanghai, Chinasity, Shanghai, China

BackgroundBackground With the increasing radiological reports of Solid pseudopapilWith the increasing radiological reports of Solid pseudopapil

lary tumor of the pancreas, its typical imaging features have lary tumor of the pancreas, its typical imaging features have been well known to radiologists. been well known to radiologists.

However, with the improvement in the imaging modalities aHowever, with the improvement in the imaging modalities and widespread use of CT and MRI, those atypical neoplasmnd widespread use of CT and MRI, those atypical neoplasms have been becoming more and more commons have been becoming more and more common. .

SOLID-PSEUDOPAPILLARY SOLID-PSEUDOPAPILLARY EPITHELIAL NEOPLASMEPITHELIAL NEOPLASM

肿瘤实质和囊性成分肿瘤实质和囊性成分 年轻女性 年轻女性 (35(35 岁岁 ) 85% ) 85% 边缘包膜清晰，境界规则边缘包膜清晰，境界规则 周缘或中心可见钙化（ 周缘或中心可见钙化（ 29% of 56 pts29% of 56 pts ）） --------------Buetow, et al. Radiology 1996; 199:707Buetow, et al. Radiology 1996; 199:707 肿瘤位于胰腺体尾部较多见肿瘤位于胰腺体尾部较多见 手术切除预后好手术切除预后好（恶性程度与肿瘤大小、年龄正比）（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

The purpose of this study was to The purpose of this study was to

investigate the accuracy of CT investigate the accuracy of CT

and MRI for diagnosis of solid and MRI for diagnosis of solid

pseudopapillary tumor of the pancrepseudopapillary tumor of the pancreas as

(SPTP).(SPTP).

Material and Material and MethodsMethods

39 patients with SPTP proven by histopathology 39 patients with SPTP proven by histopathology were divided into the were divided into the correct diagnosiscorrect diagnosis and and misdiagnosismisdiagnosis group based on the preoperative group based on the preoperative imaging and histopathologic results. imaging and histopathologic results.

All CT and MR imaging signs, including gender, All CT and MR imaging signs, including gender, age, tumor size, modalities (CT or MRI), location, age, tumor size, modalities (CT or MRI), location, shape, capsule, cystic degeneration, hemorrhage, shape, capsule, cystic degeneration, hemorrhage, calcification and enhancement type, were calcification and enhancement type, were retrospectively evaluated with a correlation to their retrospectively evaluated with a correlation to their pathologic findings and statistically analyzed.pathologic findings and statistically analyzed.

ResultsResults Among 39 imaging cases, Among 39 imaging cases, 15 (38.5%) misdiagnosed (mean age 41.07 years old)15 (38.5%) misdiagnosed (mean age 41.07 years old) 24(61.5%) diagnosed. (mean age 26.75 years old, p=0.000). 24(61.5%) diagnosed. (mean age 26.75 years old, p=0.000). Tumor size tended to be smaller in the elder group and had a negative linear correlation with the patient agTumor size tended to be smaller in the elder group and had a negative linear correlation with the patient ag

e (r=-0.408, p=0.025). e (r=-0.408, p=0.025). cause of higher misdiagnosis: cause of higher misdiagnosis: correctly diagnosis : correctly diagnosis : the older patients (p=0.007), gender, the older patients (p=0.007), gender, small tumors (p=0.037), location, small tumors (p=0.037), location, CT (p=0.049) shape, CT (p=0.049) shape, non-hemorrhage (p=0.000) capsule, non-hemorrhage (p=0.000) capsule, cystic degeneration, cystic degeneration, calcification calcification type of enhancement . type of enhancement . Macroscopically, large SPTPs were more likely to appear the capsule (p=0.002), Macroscopically, large SPTPs were more likely to appear the capsule (p=0.002), cystic degeneration (p=0.003) cystic degeneration (p=0.003) and hemorrhage (p=0.029) than small tumors. and hemorrhage (p=0.029) than small tumors.

ResultsResultsTable 1 Comparison of tumor size and age between two groups

NN Mean Mean (cm)(cm)

P valueP value

sizesize misdiagnosismisdiagnosis 1515 5.00005.0000 0.2890.289Correct Correct

diagnosisdiagnosis2424 6.11676.1167

ageage misdiagnosismisdiagnosis 1515 41.066741.0667 0.0000.000Correct Correct

diagnosisdiagnosis2424 26.750026.7500

ResultsResultsGraph 1 Linear regression analysis of tumor size and patient age

Note: Bconstant=7.435, p=0.000; Bage=-0.067, p=0.025

Table 2

imaging Analysis of SPTP between

Two groups

EvaluationsEvaluationscorrect correct diagnosisdiagnosis

misdiagnosismisdiagnosis Misdiagnosis RateMisdiagnosis Rate P valueP value

GenderGender MaleMale 33 33 50.0%50.0%

FemaleFemale 2121 1212 36.4%36.4% 0.6580.658

AgeAge ＊＊ The elder(The elder(≥40)≥40) 55 1010 66.7%66.7%

The younger(The younger(＜＜ 40)40) 1919 55 22.8%22.8% 0.0070.007

SizeSize ＊＊ Large (Large (＞＞ 3.0cm)3.0cm) 2222 99 29.0%29.0%

Small Small (≤3.0cm) (≤3.0cm) 22 66 75.0%75.0% 0.0370.037

ModalitieModalitiess ＊＊ CTCT 1111 1212 52.2%52.2%

MRIMRI 1313 33 38.5%38.5% 0.0490.049

LocationLocation HeadHead 77 66 46.2%46.2%

BodyBody 99 66 40.0%40.0%

TailTail 88 33 2.3%2.3% 0.6310.631

ShapeShape RoundRound 1111 77 38.9%38.9%

OvalOval 88 44 33.3%33.3%

LobulatedLobulated 55 44 44.4%44.4% 0.8730.873

CapsuleCapsule PresencePresence 2020 88 28.6%28.6%

AbsenceAbsence 44 77 63.6%63.6% 0.0680.068

Cystic degenerationCystic degeneration PresencePresence 1717 88 32.0%32.0%

AbsenceAbsence 77 77 50%50% 0.3180.318

hemorrhagehemorrhage ＊＊ PresencePresence 11 1111 8.3%8.3%

AbsenceAbsence 1313 1414 51.9%51.9% 0.0130.013

calcificationcalcification PresencePresence 2020 1111 35.5%35.5%

AbsenceAbsence 44 44 50%50% 0.6860.686

gradual enhancementgradual enhancement PresencePresence 2020 1212 37.5%37.5%

AbsenceAbsence 22 11 33.3%33.3% 1.0001.000

Table 3 Tumors’ demonstrations between CT and MRI

FindingsFindings CTCT MRIMRI P valueP value

CapsuleCapsule PresencePresence 1414 1414

AbsenceAbsence 99 22 0.0860.086

Cystic Cystic degenerationdegeneration

PresencePresence 1212 1313

AbsenceAbsence 1111 33 0.0930.093

hemorrhagehemorrhage PresencePresence 11 1111

AbsenceAbsence 2222 55 0.0000.000

calcificationcalcification PresencePresence 88 11

AbsenceAbsence 1515 1515 0.0280.028

gradual gradual enhancementenhancement

PresencePresence 2121 1212

AbsenceAbsence 11 22 0.5470.547

ResultsResults

ResultsResultsTable 4 Histopathological analysis in tumor size and patient age

FindingsFindings Size GroupSize Group P valueP value Age GroupAge Group P valueP value

LargeLarge SmallSmall The The elderelder

The The youngeryounger

CapsuleCapsule PresencePresence 2323 11 77 1717

AbsenceAbsence 33 55 0.0020.002 55 33 0.1160.116

Cystic Cystic degenerationdegeneration

PresencePresence 2222 11 66 1717

AbsenceAbsence 44 55 0.0030.003 66 33 0.0490.049

hemorrhagehemorrhage PresencePresence 1818 11 55 1414

AbsenceAbsence 88 55 0.0290.029 77 66 0.1500.150

calcificationcalcification PresencePresence 88 22 44 66

AbsenceAbsence 1818 44 1.0001.000 88 1414 1.0001.000

Fig. 1a

(a) Photograph of gross surgical specimen demonstrates the fibrous capsule, hemorrhagic areas and cystic degeneration.

Fig. 1.—23-year-old woman with a typical solid pseudopapillary tumor of pancreas

Fig. 1b Fig. 1cFig. 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.

Fig. 1d Fig. 1e

Fig. 1f

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

(a) Photograph of gross surgical specimen demonstrated the septations among chamberlets with cystic degeneration and the incomplete pseudocapsule.

Fig. 2.—19-year-old woman with a solid pseudopapillary tumor of pancreas misdiagnosed as mucinous cystic adenocarcinoma.

Fig. 2a

Fig. 2bFig. 2c

Fig. 2d

(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. 3 —51-year-old man with a small solid pseudopapillary tumor of pancreas.

(a) Photograph of gross surgical specimen demonstrated a small solid tumor with the thick and irregular rim.

Fig. 3a

Fig. 3bFig. 3c

Fig. 3d

(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. 4a

Fig. 4—49-year-old woman with a solid pseudopapillary tumor of pancreas misdiagnosed as an inflammatory mass.

(a) Photograph of gross surgical specimen demonstrated a relatively large solid tumor without pseudocapsule and hemorrhagic areas.

Fig. 4b Fig. 4c

Fig. 4d

(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.

ConclusionConclusion To avoid misdiagnosis, it should be very To avoid misdiagnosis, it should be very

careful to evaluate some characteristic icareful to evaluate some characteristic imaging signs in small tumors and those maging signs in small tumors and those occurred to the aged. Compared to CT, occurred to the aged. Compared to CT, MR was much superior to avoid misdiagMR was much superior to avoid misdiagnosis of SPTP. nosis of SPTP.