대한내과학회지 : 제 79 권제 6 호 2010 특집 (Special Review) - 간문부담관암의최신지견 간문부담관암 : 영상의학적진단의최신지견 서울대학교의과대학영상의학교실 한준구 Hilar Cholangiocarcinoma: Recent update of radiologic assessment Joon Koo Han, M.D., PhD Department of Radiology, Seoul National University College of Medicine, Seoul, Korea Hilar cholangiocarcinoma is an adenocarcinoma of the bile duct arising from the large bile ducts near the hepatic hilum. In this manuscript, radiologic findings and preoperative assessment techniques are described according to morphologic classification proposed by Liver cancer study group of Japan. Also, pros and cons of each imaging modalities are discussed. (Korean J Med 79:605-612, 2010) Key Words: Hilar cholangiocarcinoma; Klatskin tumor 서론담관암 (cholangiocarcinoma) 은담관상피세포에서기원하는선암 (adenocarcinoma) 으로간세포암에이어간에서발생하는두번째로흔한원발암이다 1). 담관암은간내담관암과간외담관암으로분류되며이중간내담관암은다시주변부담관암과간문부담관암으로나눠진다. 주변부담관암과간문부담관암은종괴가어디에서부터시작되었는지에따라구분하며그기준은간내담관 2차분지부이다. 그러나간내담관 2차분지부근처담관의어느한곳에서발생하여양쪽에걸쳐있는종괴의경우앞서의두담관암중어느쪽인지명확하게밝히지못할수있다. 마찬가지로총간관분지부나좌우간내담관 1차분지에서발생하는간문부담관암도간외담관암과명확하게구분되지않는경우가종종있다. 발생빈도를보면주변부담관암이전체담관암의 10% 를차지하며간문부담관암은 25%, 간외담관암은 65% 를차지한다 2). 형태학적으로는다양한분류가사용되는데, 일본간암연구회 (Liver Cancer Study Group of Japan) 에서는종괴의성장 특성에따라종괴형성형 (mass-forming type), 담관내발육형 (intraductal-growing type), 담관주위침윤형 (periductal-infiltrating type) 으로구분하는분류법을제안했다 ( 그림 1) 3). 이들이제시한분류는종괴의육안소견, 성장양상, 생물학적행태, 환자의예후등과잘일치하며영상의학소견에도잘부합하여가장합리적인분류법으로여겨지고있다. 담관암의영상진단에는주로횡단면영상기법인초음파, 전산화단층촬영 (computed tomography, CT), 자기공명영상 (Magnetic resonance imaging, MRI) 등이사용되고있으며침습적방법으로경피경간담관조영술, 내시경적역행성췌담도조영술 (Endoscopic retrograde cholangiopancreaticography, ERCP), 수술중담관조영술이사용된다. 일반적으로초음파는일차적인선별검사로사용되며, CT와 MRI가병기결정을위한검사로사용된다. 담도조영술은중재적시술을위한검사또는수술전정확한담도의침범범위의판정을위하여사용된다. 간문부담관암은정의상간내담관암의일부로분류되고있지만그임상양상이나방사선학적소견, 수술적치료방법 - 605 -
- The Korean Journal of Medicine: Vol. 79, No. 6, 2010 - A B C Figure 1. Drawings illustrate various types of intrahepatic cholangiocarcinoma as classified by the Liver Cancer Study Group of Japan. (A) Mass-forming intrahepatic cholangiocarcinoma manifests as a round mass with a distinct border in the liver parenchyma. (B) Periductal infiltrating intrahepatic cholangiocarcinoma is characterized by tumor infiltration along the bile duct (arrow). It occasionally involves the surrounding blood vessels or hepatic parenchyma. (C) Intraductal intrahepatic cholangiocarcinoma is characterized by papillary or granular growth within the bile duct lumen. It occasionally demonstrates superficial extension (right arrow) or forms a tumor thrombus in an obstructed duct (left arrow). More than one type of cholangiocarcinoma may manifest in a single patient. In such cases, all of the types involved should be recorded (eg, periductal infiltrating intraductal ) (reprinted from 8). Figure 2. Types of hepatic duct obstruction caused by hilar cholangiocarcinoma. Type I is a nonobstructed primary confluence; type II, obstruction limited to the primary confluence; type III, an obstructed primary confluence with extension to the right (type IIIa) or left (type IIIb) secondary confluence; and type IV, an obstructed secondary confluence of both the right and left hepatic ducts. (Adapted and reprinted, with permission, from reference 7.) 등은간외담관암과좀더유사한양상을보여일부교과서에서는이두질환을 대담관암 (large duct cancer) 혹은 담관암종 (carcinoma of the bile duct) 등으로묶어기술하기도한다. 간문부담관암은주담관에서발생하는악성종양의 50% 이상을차지한다. 주담관암의약 17% 와 18% 에서각각중간및 원위부총담관을침범하며약 7% 에서미만성종양침윤을보인다 4-6). 간문부담관암은간내담도분지의침윤정도에따라 Bismuth I형에서 IV형까지분류한다. I형은좌, 우담관합류부의폐쇄가없는형태, II형은합류부에폐쇄가국한되어있고 2차분지이하의침범이없는형태, III형은합류부의폐쇄가있고, 좌, 우담관분지중한쪽의 2차분지이상이침범된형태로우측침범이면 IIIa형, 좌측침범이면 IIIb형이다. IV형은양측모두 2차분지이상이침범된형태이다 ( 그림 2). 간내담관암과마찬가지로자라는모양에따라종괴형성형, 주변부침윤형및담관내발육형의세가지로구분하나이세가지기본형태에다른형태가공존하는복합형 combined을덧붙여서분류하기도한다 7,8). 종괴형성형간문부담관암종괴형성형간문부담관암은같은타입의주변부담관암의소견과유사하게주변부테두리가조영증강된큰저음영종괴로보이며, 간문부담도의폐쇄가동반되어있다는점에서주변부담관암과구별된다. 간혹종괴가간문부에서자랐는지아니면주변부담관암이이차적으로간문부를침범하여폐쇄시킨것인지를정확하게감별하는것이쉽지않거나불가능한경우도있다 ( 그림 3) 8). - 606 -
- Joon Koo Han. Hilar Cholangiocarcinoma: Recent update of radiologic assessment - A B C Figure 3. Exophytic hilar cholangiocarcinoma. Arterial (A) and portal-phase (B) computed tompgraphy (CT) scans show a 4-cm low-attenuation mass with peripheral enhancement at the hepatic hilum, mainly in segment IV. Both intrahepatic ducts are dilated. Two pigtail catheters were inserted for drainage. (C) Cholangiogram reveals obliteration of the hilar ducts. In such case, it is difficult to ascertain whether the tumor originates from the left hepatic duct and demonstrates exophytic growth or originates from a small branch of segment 4 and exhibits subsequent involvement of the hepatic hilum (reprinted from reference 8). A B Figure 4. Polypoid hilar cholangiocarcinoma. (A, B) Delayed- phase computed tompgraphy (CT) scans (B obtained at a lower level than A) show a soft-tissue mass (arrow) within a dilated left hepatic duct and common bile duct. (C) Cholangiogram shows a polypoid mass at the confluence level (arrows) (reprinted from reference 8). C 담관내발육형간문부담관암담관내발육형간문부담관암은주위간실질에비해저음영을가진담관내연조직성종괴로보인다 ( 그림 4) 9). 종양은흔히담관계내에다발성혹은파종성으로존재하며양측간내담관이나간외담관을동시에침범하기도한다. 육안적으로관찰되는것보다현미경소견상병변의침범부위가훨씬큰경우가흔하므로수술전병기결정시담도내시경등을이용한적극적인종양범위판정이필요하다. 병변의위치에 따라발현증상이결정되는데, 주담관에위치하면황달이, 간내담관에위치하면우연히발견된분절성담관확장이나타난다. ERCP 및경피경간담관조영술에서는늘어난담관내혹은담관벽을따라유두상종괴가불규칙하고, 톱니바퀴같은변연을가진충만결손으로나타난다 9,10). 최근담관내에서유두상으로성장하는종양중풍부한점액분비가특징인변이종, 즉담관내유두상점액종양 intraductal papillary mucinous tumor (IPMT) of the bile duct에대한관심이높아지고 - 607 -
- 대한내과학회지 : 제 79 권제 6 호통권제 604 호 2010 - 있다. 이질환은내시경으로십이지장유두의벌어진입구를통해분비되는점액을확인함으로써진단할수있는데, 이종양은병리학적소견, 다량의점액분비, 병태생리학적특성면에서췌장의관내유두상점액종양과유사성이많고, 종괴의근위부및원위부담관이모두심하게늘어난다. 초음파와 CT에서점액은각각무에코나물과같은정도의음영을보여담즙과구별되지않는게보통이다. 종괴자체는보이지않거나초음파성고에코나 CT상저음영의작은병변으로보일수도있다 ( 그림 5) 9-11). 담관주위침윤형간문부담관암담관주위침윤형은총간문부담관암의 70% 이상을차지하는가장흔한타입이다. 병리학적으로암조직이담관벽을따라침윤성으로증식함에따라담관벽이두꺼워지고담관이완전폐쇄되며주위혈관이나간실질을침범한다. 초음파에서좌우간내담관의확장이보이며간문부에서확장된좌우담관은서로합류되지않고분리되어보인다. 회색조영상만으로는종괴자체를보기힘들수있으나미세기포조영제를이용한조영증강영상에서는종괴자체뿐아니라근위부경계와간실질침범등종양의범위와주변위성 A B C Figure 5. Intraductal papillary mucinous tumor of the bile duct. (A) computed tomography (CT) shows a small papillary tumor in the cystic duct (arrow). (B) Distal common duct is dilated without definite obstructing cause. The patient complained of recurrent right upper quadrant pain and fever. (C) endoscopic retrograde cholangio pancreatography (ERCP) shows amourphous filling defect in distal common duct, suggesting intraductal mucin. Segmental resection of mid common duct revealed papillary adenocarcinoma in the cystic duct. - 608 -
- 한준구. 간문부담관암 : 영상의학적진단의최신지견 - A B C D Figure 6. Infiltrating hilar cholangiocarcinoma with tumoral involvement of the right secondary confluence and common hepatic duct. (A) CT scan reveals a high-attenuation tumor on the anterior aspect of the right portal vein (arrowheads). (B) On a subsequent computed tomography (CT) scan, the tumor appears as a high-attenuation lesion on the right side of the portal vein (arrowheads). (C, D) CT scans (D obtained at a lower level than C) show the mucosa of the cystic duct with strong enhancement (open arrow), a finding that suggests tumoral involvement. Soft tissue infiltration around the portal vein (arrowheads) and lymphadenopathy (solid arrow) are also noted (reprinted from 8). - 609 -
- The Korean Journal of Medicine: Vol. 79, No. 6, 2010 - 결절등을더잘보여줌으로써술전병기결정에도움을줄수도있다 12). 조영증강 CT에서담관주위침윤형종괴는담관을폐쇄시키는국소적담관비후의형태로나타나며동맥기에는고음영을보이는경우가많고문맥기에도등음영혹은고음영을보여대략 80% 이상에서동맥기또는문맥기에주변간실질보다높은조영증강을보인다 ( 그림 6) 7,8). 폐쇄위치와담관침범범위의정확한평가는좌우담관의 2차합류부를얼마나정확히확인할수있느냐에달려있다. 초기나선CT는약 60% 의정확도를보인다고보고되었으나보다발전된 MDCT 와담도조영술을혼합하면 84% 에서정확한진단이가능하다 7,8,13). 담관암의혈관침범은종괴와혈관사이의지방층이유지되느냐, 혈관주위에연부조직음영이존재하느냐, 그리고역동적 CT상보상성혈류증가소견이있느냐로진단한다 ( 그림 7). CT는혈관침범을예측하는데비교적정확하고유용하여동맥및문맥침범을모두 90% 이상의정확도로판정할수있다 13,14). 간문부담관암의수술적절제가능성은혈관침범과담도침범의정도에따라예측한다. 통상적으로절제불가능한간문부담관암은 Bismuth IV형담도침범, 주문맥또는고유간동맥침범, 한쪽의혈관침범과반대쪽담도의 2차분지이상침범, 한쪽의간엽위축과동반된반대측담도의 2차분지침범이나혈관침범등이있다. 최근에는간문부에서담도나혈관분지의정상변이가매우많은점, 또수술기법이발전되어혈관침범시절제후문합 (resection and anstomosis) 이가능한경우가증가함감안하여간문부에서부터 2 cm 이내의담도침범이나 2 cm 길이미만의혈관침범은절제가능한암으로분류한다 ( 표 1) 13). MRI에서종양은 CT와비슷하게동맥기에고신호강도, 문맥기에등신호강도혹은고신호강도의조영증강을보인다. MRCP의주소견은담관의연결성이소실되거나담관폐쇄, 급격하고불규칙적인담관내경의감소와상부담관의확장, 담관내불규칙한모양의충만결손등이다 ( 그림 8). 종양의담관내침범범위결정에서 MR과 MRCP는 CT 및담관조영술과유사하게 85% 이상의진단정확도를보인다 14,15). 담관암의병기결정에있어담관주위침윤형은담관내발육형보다높은일치율을보인다 16). 이는담관내발육형종양은다발성이며점막을따라표재성으로파급되어병변들사이사이에정상점막이끼어있는양상을보이기때문에병변의 Figure 7. Hepatic arterial invasion is seen as a soft tissue infiltration around the right hepatic artery (arrows). Table 1. Criteria for unresectability of hilar cholangiocarcinoma (modified from reference 13) Criteria Bismuth type IV (and tumor extends farther than 2 cm from the hilum) Invasion of main portal vein or proper hepatic artery (plus involved segment is longer than 2 cm) Atrophy of one hepatic lobe with contralateral vascular invasion Atrophy of one hepatic lobe with contralateral tumor extension to second biliary confluence Invasion of second biliary confluence on one lobe and contralateral vascular invasion Metastasis to celiac, portocaval or paraaortic LNs Distant metastasis Evaluation Tool CT and cholangiography CT CT CT and cholangiography CT and cholangiography CT CT - 610 -
- Joon Koo Han. Hilar Cholangiocarcinoma: Recent update of radiologic assessment - A B C Figure 8. A 66-year-old man with Bismuth type IIIb hilar cholangiocarcinoma. (A) Coronal thick slab T2W TSE MRC (T2 weighted turbo spin echo magnetic resonance cholangiogram) image shows separation of the left secondary branches of the intrahepatic duct, suggesting involvement of the left secondary confluence (arrows). (B) Gadolinium-enhanced T1W (T1 Weighted) image shows a mass as a focal enhancement of the thickened ductal wall at the right intrahepatic duct (arrowheads). (C) Axial thin slab T2W HASTE MR (T2 weighted Half-fourier acquisition single shot turbo spin echo magnetic resonance) image shows dilatation of the bile duct (arrows). Mass is not clearly demonstrated int2 weighted images (reprinted from 15). 정확한범위파악이힘든데기인한다. 이처럼 MRCP 의진단정확도는매우높으며, 기기의발전에따라검사시간이단축되고고해상도의영상획득이가능해짐에따라진단적담관조영술을대신하고있다. 침습적인고식적담췌관조영술과비교한 MRCP의장점은비침습적이며조영제주입이필요없어합병증이전혀없다는점, 주담관과의연결성이없는담관도관찰할수있어소위 missing duct 를잘평가할수있다는점, 직접담도조영술에서는얻을수없는다양한각도에서담도관찰이가능하다는점, 고식적 MRI와같이시행하여담관주위로의병변의파급, 예를들면혈관침범, 림프절비대등을동시에평가할수있다는점등이다. 이에따라 MR은 one-stop service 로서그사용이늘어나고있다. 그러나 MR은고해상도영상이가능한기기나이를판독할수있는전문인력이제한적이며, 또영상획득범위가상복부만으로제한됨에따라복강내다른부분에대한정보가제한적이라는단점을가지고있다. 결론결론적으로간문부담관암은육안적소견에따라종괴형성형, 담관내발육형, 주변부침윤형의세가지로분류할수있으며, MDCT 와담도조영술의조합또는 MRI와 MRCP의조합에의하여비교적정확한진단과절제가능성을예측할수있다. 그러나일부담도암에서는육안적소견으로도식별하기어려운표재성파급을동반하여정확한병변의범위예측이어려운경우가있고, 이런병변에대해서는수술전혹은수술중담도내시경및생검등의침습적인검사가필 요하다. 중심단어 : 간문부, 담관암 REFERENCES 1) Nakajima T, Kondo Y, Miyazaki M, Okui K. A histopathologic study of 102 cases of intrahepatic cholangiocarcinoma: histologic classification and modes of spreading. Hum Pathol 19:1228-1234, 1988 2) Clemett AR. Carcinoma of the major bile ducts. Radiology 84:894-903, 1965 3) Liver Cancer Study Group of Japan. The general rules for the clinical and pathological study of primary liver cancer. 4th ed. Tokyo, Kanehara, 2000 4) Choi BI, Han JK, Kim TK. Benign and malignant tumors of the biliary tree. In: Gazelle SG, ed. Hepatobiliary and pancreatic radiology. p. 630-676, New York, Thieme, 1998 5) Choi BI, Han JK, Kim TK. Diagnosis and staging of chol-angiocarcinoma by computed tomography. In: Meyers MA, ed. Neoplasms of the digestive tract: imaging, staging and management. p. 503-516, Philadelphia, Lippincott-Raven, 1998 6) Tompkins RK, Saunders K, Roslyn JJ, Longmire WP Jr. Changing patterns in diagnosis and management of bile duct cancer. Ann Surg 211:614-620; discussion 620-621, 1990 7) Han JK, Choi BI, Kim TK, Kim SW, Han MC, Yeon KM. Hilar cholangiocarcinoma: thin-section spiral CT findings with cholangiographic correlation. Radiographics 17:1475-1485, 1997 8) Han JK, Choi BI, Kim AY, An SK, Lee JW, Kim TK, Kim SW. Cholangiocarcinoma: pictorial essay of CT and cholangiographic findings. Radiographics 22:173-187, 2002 9) Lee JW, Han JK, Kim TK, Kim YH, Choi BI, Han MC, Suh KS, - 611 -
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