대한내과학회지 : 제 87 권제 3 호 2014 http://dx.doi.org/10.3904/kjm.2014.87.3.261 특집 (Special Review) - 췌장낭성종양의최신경향 췌장낭성종양의영상학적감별 순천향대학교의과대학순천향대학교서울병원영상의학과 홍성숙 Radiologic Findings of Pancreatic ystic Neoplasms Seong Sook Hong Department of Radiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University ollege of Medicine, Seoul, Korea With the widespread use of radiologic modalities such as ultrasonography (US), computed tomography (T), and magnetic resonance imaging (MRI), cystic neoplasms of the pancreas are being increasingly detected; however, developing an accurate characterization and making a differential diagnosis are difficult because of their overlapping morphologic characteristics. Serous cyst adenoma is a common benign neoplasm that is typically observed as a multi-cystic mass or lobulated cyst with or without internal septation. In comparison, mucinous cystic neoplasms appear as smooth cystic tumors with or without internal septation. Finally, intraductal papillary mucinous neoplasms of the pancreas are pleomorphic cystic lesions or clubbed fingerlike tubular structures. These typical imaging findings can help clinicians differentiate cystic neoplasms of the pancreas. (Korean J Med 2014;87:261-269) Keywords: Pancreas cyst; Pancreas neoplasm; Pancreas T; Pancreas MRI 서론췌장의낭성종양은영상진단기기가발전하고검사증가로인하여점점낭성종양에대한검출이증가되는추세이다. 일부낭성종양은형태학적특성이매우특이적인부분이있어영상소견만으로감별진단이용이한경우가있으나낭성종양들의형태학적소견이중복되는부분이많아특성화와감별이용이하지않는점도많다. 췌장의낭성종양은수술한예중약 10-15% 를차지하는것으로보고되고있으 나수술하지않은증례에서도우연히발견되어추적검사하는증례가많아실제발생빈도는훨씬높을것으로보인다 [1-4]. 이런췌장의낭성종양의영상의학적특성및감별점에대하여기술하고자한다. 본론췌장의원발성낭성종양은수술한예중 10-15% 정도이며장액성낭종과점액성낭종, 관내유두상점액성종양으로 orrespondence to Seong Sook Hong M.D., Ph.D. Department of Radiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University ollege of Medicine, 59 Daesakwan-ro, Yongsan-ku, Seoul 140-743, Korea Tel: +82-2-709-9396, Fax: +82-2-709-3928, E-mail: hongses@schmc.ac.kr opyright c 2014 The Korean ssociation of Internal Medicine This is an Open ccess article distributed under the terms of the reative ommons ttribution - 261 - Non-ommercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
- The Korean Journal of Medicine: Vol. 87, No. 3, 2014 - 나누어진다. 췌낭의낭성종양에대한초기검사로 MDT 나 MRI가선택되고있는데비교적쉽고정확하게진단에접근할수있다. 복부 T의 2.6% 에서췌장낭종이우연히발견되며복부 MRI의 20% 에서낭성종양이발견되는것으로보고될만큼발견율이높은질환이다 [5-8]. 그러나 MDT 의진단정확도는 56-85% 로 MRI에비하여약간낮다 [9-12]. 이는 MRI는연부조직해상도가뛰어나기때문으로해석되는데, 또한췌장과담관을비침습적으로보여주는장점이있으며막힌부위의근위부까지영상으로보여주어현재널리이용되고있다. 또한최근기기의발달로 MRI에서도췌관과연결을다평면을통하여잘보여줄수도있다. 내부의격막이나고형병변의동반유무를보여주는 EUS와비교하여도민감도 94.4%, 정확도 90-98% 를보여두진단법이통계상유의한차이가없음을보여준다 [13]. 점액성낭성종양 (mucinous cyst neoplasm) 점액성낭성종양은췌장의낭성종양중가장흔한종양으로양성과악성으로구분되나양성의경우도악성으로전환되는전구단계로생각되므로완전절제를해야한다. 점액을분비하는다양한비정형상피세포로구성되며췌장과연 결되지않는난소형태기질에의해지지되고있다. 85% 에서췌부와미부에서발생하며 50% 에서 40-50대에호발하고여성에많이발생한다 [14-16]. 낭종의평균크기는 12 cm이고외표면이평활하며단방성이나다방성의큰낭종으로구성된다. 낭종의벽은 1-2 mm 정도이고 1/6에서석회화가있다. 장액성낭종에비해격막이좀더두껍고더불규칙하며낭종내부에더작은낭이나고형유두상성장물이있을수있다 (Fig. 1) [15,16]. 주변장기로의침윤이나혈관의침범등소견을보일때는뚜렷한악성을시사하지만대개의경우악성과의감별이쉽지는않은데다방성의거대한낭성종괴, 두꺼운벽, 고형병변, 벽과격막의석회화등은악성을시사한소견이다. 초음파검사나 T 영상에서원형이나난원형으로외표면이평활하고거의물밀도와같은종괴로초음파에서격막과고형성분을잘관찰하면진단에도움을받을수있다. T 영상에서낭종내에다른감쇠를보이는경우가있는데, 이는내부의점액질의농도가달라서이거나출혈이발생하여보이게되며이런소견은점액성낭성종양을감별하는중요한감별점이되기도한다 [17]. MR에서종양의신호강도는내부성분에따라다양하게 Figure 1. Mucinous cystic neoplasm of the pancreas with low grade dysplasia. Portal phase enhanced T () shows a multiple septated well-defined cystic mass at pancreatic tail. oronal reformatted T scan () shows a well-circumscribed mass within multiple fine-septa which were well enhanced. This lesion was confined mucinous cystic neoplasm of the pancreas with low grade dysplasia after surgical resection. - 262 -
- Seong Sook Hong. Radiologic findings of pancreatic cystic neoplasms - D Figure 2. Mucinous cystic neoplasm of pancreas with invasive adenocarcinoma. Ultrasonography () shows a large anechoic cyst in left upper abdomen. Enhanced T () presents a large cystic mass in pancreatic tail portion within an enhanced papillary mural nodule. T1 weighted image () and T2 weighted image (D) show a high signal intensity unilocular and well-circumscribed cyst and has a mural nodule, which is suspected malignancy. This lesion was confined mucinous cystic neoplasm of pancreas with invasive adenocarcinoma after distal pancreatectomy. 보이는데 T보다이런소견이더욱뚜렷이관찰되기도한다. T1강조영상에서대부분의낭종은저신호강도로나타나나내부에출혈혹은점액농도가높아단백질이있을경우는고신호강도로나타나는특징이있다. 가돌리늄조영증강영상에서낭종의벽과격막이조영증강되어보이며악성종괴의경우는낭종내에유두상종괴나낭종을가득채우는종괴등으로나타나며이부위가강한조영증강을보인다 (Fig. 2) [16]. 장액성낭종 (serous cystadenoma) 췌장의장액성낭종은췌장의낭성종양중두번째로흔하며외분비췌장질환의 1-2% 를차지한다. 주로췌장의두 부에호발하나췌장의어느부위에나발생할수있다. 낭종의크기는다양하여 5-10 cm 가량의큰낭종을형성하는경우와 1-20 mm의작은낭종을형성하는경우로나눌수있다 (Fig. 3). 점액성낭종보다석회화가좀더호발하며중년여성에서호발하는경향이있다 [17]. 낭종의형태에따라두가지형즉, 미세낭종 (microcystic) 과대낭종 (macrocystic) 혹은소수낭종 (oligocystic) 으로나누어지며이런형태학적분류에따라영상소견을달리한다. 대낭종형은낭선종내의낭종크기가 2 cm 이상으로크고단방성이거나 6개미만의다방성이며중앙반흔이없어영상소견만으로점액성낭선종과감별이매우어렵다. 이런다방성의형태가가장흔한형태학적소견으로보이며점액성낭선종과의감별은경계가좀 - 263 -
- 대한내과학회지 : 제 87 권제 3 호통권제 649 호 2014 - D Figure 3. Serous oligocystic adenoma of pancreas. ontrast enhanced T scan () during portal phase shows lobulated contoured cystic mass in pancreas neck. MRP () and T1-weighted enhancing axial MR image () show that this mass has many internal lobules and subtle enhancing septa. There is no pancreatic ductal dilatation or calcification. 더엽상형이거나여러개의다양성낭종으로구성되어있고점액성낭선종은좀더경계가매끈하면서내부가격막으로나누어져있는형태를보여감별할수있다 [16,17]. 두번째로흔한형태학적소견은벌집모양 (honeycomb) 혹은해면상 (sponge-like) 종괴로나타나는경우인데여러개의작은낭종과섬유성격막으로인하여해면상으로나타나는경우인데미세낭종에서흔하게보이는소견이다. 이런미세낭종의경우는신경내분비성종양 (islet cell tumor) 과감별이어려운경우가있는데이때에는췌장조영기에조영증강되는 점으로구분하려는시도를해볼수있다. 그리고신경내분비성종양의경우는크기가커지면내부에괴사나출혈에의하여다양한밀도로나타난다. 단순복부사진에서중앙반흔에생긴이영양증석회화 (dystrophic calcification) 가낭종의 1/3 정도에서보일수있는데중앙에햇살모양으로나타날수있다. 초음파검사에서낭종크기에따라다양하게나타나는데가장흔한소견은다발성의작은낭종이있는저에코병변으로나타나스폰지같은병변으로나타나기도하고고형종괴내부에매우작은여 - 264 -
홍성숙. 췌장 낭성 종양의 영상학적 감별 Figure 4. ranch duct IPMN of the pancreas. US () shows the pancreatic anechoic cyst at pancreatic body portion. MR T2 weighted image shows grape-like clustered multiple cysts at pancreatic body with mild upstream duct dilatation. MRP () shows multiple clustered cysts that communicate with the pancreatic duct dilatation. Figure 5. ranch duct IPMN with malignant transformation of the uncinate process of the pancreas. ontrast enhanced T on portal phase () shows multiple clusted cystic mass with enhancing mural nodules and thicken of the septa. T1-weighted MR image () shows low signal intensity cystic mass and T2-weighted MR image () shows high signal intensity cystic mass with thickening of septa which is suggestive of malignancy. 러 개의 낭종이 들어 있는 모양으로 나타나기도 한다. 각각 에 의한 고신호를 보이게 되는데 작은 낭종과 내부의 격막 의 낭종이 커지면 규칙적인 얇은 벽을 이루는 분명한 무에 이 보이며 격막은 경미하게 조영 증강되고 내부의 중심반흔 코성 종괴로 나타난다. 내부에 중앙 석회화가 있을 경우는 은 지연된 조영 증강을 보인다. 혈관조영술에서 격막 내 모 후방음영 감쇄로 알 수 있다[18]. 세혈관 네트워크에 의하여 과혈관성 종괴로 나타난다. T에서는 저밀도의 피막화 분엽성 종괴(encapsulated lobu- 감별해야 하는 질환으로는 단발성 낭종으로 보일 때는 점 lated mass)로 보이며 격막이 조영 증강되어 벌집모양 혹은 액성 낭종 종양과 감별이 매우 어렵고 가성낭종(pseudocyst) 스위스치즈(swiss-cheese) 모양으로 나타나고 중앙 석회화가 도 감별해야 한다. 고형종괴로 나타나는 미세낭종일 경우는 섬유성 반흔 내에 나타날 수 있다. 원위부 췌장 실질의 위축 췌장암이나 신경내분비성 종양, 고형가성유두종양 등과 감 이나 췌관의 확장은 거의 동반되지 않는다. 이는 중심부의 별을 요한다. 괴사나 출혈이 진행된 신경내분비성 종양의 경 격막이나 섬유화 성분이 많을수록 조영 증강되는 부분이 많 우는 점액성 낭종에 비하여 피막(capsule)이 두껍게 보인다. 최근 Diffusion-weighted MRI영상을 이용하여 췌장의 낭종 아지면서 고형의 종괴로 오인되어 나타나기도 한다. T1강조영상에서는 액체성분으로 인하여 저신호강도를 나 을 감별하려는 노력도 시도되고 있는데 췌장의 낭성 종양과 타내는 경우가 흔하고, MR T2강조영상이 특징적으로 낭종 화농성 종양에서 가성낭종에 비하여 고신호강도를 보이는 - 265 -
- The Korean Journal of Medicine: Vol. 87, No. 3, 2014 - D Figure 6. Main duct IPMN with malignant transformation of the pancreas head. T2-weighted axial MR image () shows diffuse main pancreatic duct dilatation and multiple branch duct dilations. T2-weighted axial MR image () at pancreas head shows multiple clustered cystic mass with enhancing solid portions that is presented malignant transformation. MRP () shows diffuse dilatation of main and branch ducts and also shows abrupt luminal narrowing of d-d and pancreatic duct of head portion due to tumor invasion. Fat saturated T1-weighted axial MR image (D) after gadolinium enhancement shows enhancing mural nodules in the clustered cystic mass at pancreas head. 것으로보고되고있다 [19]. 점액성낭종이췌장전체에걸쳐광범위하게퍼져있는경우 von Hippel-Lindau 질환을의심해봐야한다. 관내유두상점액성종양 (intraductal papillary mucinous tumor, IPMN) IPMN 은주췌관이나췌관의분지를이루는상피세포에서끈적한점액을분비하여담관의확장과폐쇄를일으키는낭성종양이다. 이는발생부위에따라 1) 주췌관 (main duct - 266 -
- Seong Sook Hong. Radiologic findings of pancreatic cystic neoplasms - type) 과분지관 (branch duct type) 형태로나누거나 2) 결합형으로나눌수있다. 이런분류에따라각각다른영상소견을보이게된다 [20]. 주췌관에서발생할경우미만성이나분절성관확장을일으키고분지관에서생기는경우주로구상돌기를침범하여포도송이모양으로낭종이몰려있는모양으로나타난다 (Fig. 4). T나 MRI 영상소견은다발성낭종이포도송이모양으로나타나며주로구상돌기에나타나는경우가많다. 확장된췌관과연결이직접관찰되는경우가많아졌다. 악성을예측할수있는소견은고형종괴가보이고주췌관이 10 mm 이상확장되고, 미만성혹은다발성침범, 내부성분이고밀도나췌관내석회화가있을때, 가성격막의개수가많을때, 팽대부가팽창되어있을때, 당뇨병이동반되어있을때라고보고하고있다 (Figs. 5 and 6) [20]. 다른낭종인점액성낭종이나장액성낭종과의감별점으로는낭성구조가원형보다는타원형이고곤봉모양형손가락모양을보이거나다형태 ( 원형과타원형이단면에서섞여있는 ) 를보이고주췌관과연결되어주췌관의확장을동반한것을확인하면진단할수있다. 십이지장내로팽대된팽대부, 주췌관의확장등이동반된주요한소견이다 [16]. 기타 Figure 7. alcified pseudocyst. ontrast enhanced T shows a large cystic mass that has dense curvilinear calcification in the peripheral wall. These findings are suggestive of calcified pseudocyst. 고형가성유두종양 (solid pseudopapillary tumor, SPT) 이나신경내분비종양의경우일반적으로는영상소견에서조영증강되는고형종괴로나타나지만내부에다양한정도의출혈이나낭성변성이쉽게동반되고이런변성부위가커지면낭성종양과감별이어려운경우가종종있다. 이밖에도 Figure 8. Neuroendocrine tumor with cystic degeneration mimicking IPMN. T2-weighted axial MR image () shows multiple clustered cysts in pancreatic tail, MRP () revealed the cystic mass communicated with dilated pancreatic duct. These findings are suggestive of IPMN at the pancreas tail but final diagnosis after surgical resection revealed neuroendocrine tumor. - 267 -
- 대한내과학회지 : 제 87 권제 3 호통권제 649 호 2014 - 석회화된출혈성가성낭종의경우도낭성종양과감별진단이어려운경우가있다 (Figs. 7 and 8). 결 췌장의낭성종양은영상소견에서다양하게나타날수있고감별진단에많이겹쳐지는형태학적소견이있어혼돈을주는경우가많다. 그러나장액성낭종은양성종양이며다발성격막을지니고있고경계가좀더엽상형으로보이며중심반흔과석회화의동반이많아좀더감별점을보인다. 점액성낭성종의악성종양의가능성이높아감별을요하는데경계가좀더매끈한낭종으로보이며내부에다양한정도의격막을동반하며격막내단백질이나출혈의동반등으로인하여격막마다약간다른신호강도를갖기도하는특징이있다. 관내유두상점액종은발생부위에따라모양을달리하여나타나나췌관확장으로인해곤봉형손가락모양으로늘어난췌관으로인하여단면상에서원형보다는타원형혹은관상구조를보이는경우가많고주췌관의확장이동반되어나타나는경우가흔하다. 장액성낭성종에서도담관확장이동반될수있는데이때는종양에의하여눌려서상부의췌관이늘어나는경우가많다. 이런췌장낭성종의형태학적특성에익숙해지면낭성종양의정확한진단과치료에도움을줄수있다. 중심단어 : 췌장낭종 ; 췌장종양 ; 췌장 T; 췌장 MRI 론 REFERENES 1. Wolfman NT, Ramquist N, Karstaedt N, Hopkins M. ystic neoplasms of the pancreas: T and sonography. JR m J Roentgenol 1982;138:37-41. 2. Visser, Yeh M, Qayyum, Way LW, Mculloch E, oakley FV. haracterization of cystic pancreatic masses: relative accuracy of T and MRI. JR m J Roentgenol 2007;189:648-656. 3. Sainani NI, Saokar, Deshpande V, Fernández-del astillo, Hahn P, Sahani DV. omparative performance of MDT and MRI with MR cholangiopancreatography in characterizing small pancreatic cysts. JR m J Roentgenol 2009;193:722-731. 4. Demos T, Posniak HV, Harmath, Olson M, ranha G. ystic lesions of the pancreas. JR m J Roentgenol 2002;179:1375-1388. 5. Sahani DV, Kambadakone, Macari M, Takahashi N, hari S, Fernandez-del astillo. Diagnosis and management of cystic pancreatic lesions. JR m J Roentgenol 2013;200: 343-354. 6. Laffan T, Horton KM, Klein P, et al. Prevalence of unsuspected pancreatic cysts on MDT. JR m J Roentgenol 2008;191:802-807. 7. Lee HJ, Kim MJ, hoi JY, Hong HS, Kim K. Relative accuracy of T and MRI in the differentiation of benign from malignant pancreatic cystic lesions. lin Radiol 2011;66:315-321. 8. Zhang XM, Mitchell DG, Dohke M, Holland G, Parker L. Pancreatic cysts: depiction on single-shot fast spin-echo MR images. Radiology 2002;223:547-553. 9. Sahani DV, Sainani NI, lake M, rippa S, Mino- Kenudson M, del-astillo F. Prospective evaluation of reader performance on MDT in characterization of cystic pancreatic lesions and prediction of cyst biologic aggressiveness. JR m J Roentgenol 2011;197:W53-61. 10. Sainani NI, Saokar, Deshpande V, Fernández-del astillo, Hahn P, Sahani DV. omparative performance of MDT and MRI with MR cholangiopancreatography in characterizing small pancreatic cysts. JR m J Roentgenol 2009; 193:722-731. 11. Kawamoto S, Lawler LP, Horton KM, Eng J, Hruban RH, Fishman EK. MDT of intraductal papillary mucinous neoplasm of the pancreas: evaluation of features predictive of invasive carcinoma. JR m J Roentgenol 2006;186: 687-695. 12. Procacci, arbognin G, ccordini S, et al. T features of malignant mucinous cystic tumors of the pancreas. Eur Radiol 2001;11:1626-1630. 13. Kim Y, hoi JY, hung YE, et al. omparison of MRI and endoscopic ultrasound in the characterization of pancreatic cystic lesions. JR m J Roentgenol 2010;195:947-952. 14. ohen-scali F, Vilgrain V, rancatelli, et al. Discrimination of unilocular macrocystic serous cystadenoma from pancreatic pseudocyst and mucinous cystadenoma with T: initial observations. Radiology 2003;228:727-733. 15. Handrich SJ, Hough DM, Fletcher JG, Sarr MG. The natural history of the incidentally discovered small simple pancreatic cyst: long-term follow-up and clinical implications. JR m J Roentgenol 2005;184:20 23. 16. Kim SY, Lee JM, Kim SH, et al. Macrocystic neoplasms of the pancreas: T differentiation of serous oligocystic adenoma from mucinous cystadenoma and intraductal papillary mucinous tumor. JR m J Roentgenol 2006;187:1192-1198. 17. Kim HJ, Lee DH, Ko YT, Lim JW, Kim H, Kim KW. T of - 268 -
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