8 Liver Hemangioma. 8.1 Introduction. 8.2 Sonography. Valérie Vilgrain and Giuseppe Brancatelli

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1 Liver Hemngiom Liver Hemngiom Vlérie Vilgrin nd Giuseppe Brnctelli CONTENTS 8.1 Introduction Sonogrphy Computed Tomogrphy Mgnetic Resonnce Scintigrphy Percutneous Biopsy Atypicl Ptterns Hemngiom with Echoic Border Lrge, Heterogeneous Hemngiom Rpidly Filling Hemngiom Very Slow Filling Hemngiom Clcified Hemngiom Hylinized Hemngiom Cystic or Multiloculr Hemngiom Hemngiom with Fluid Fluid Level Pedunculted Hemngiom Hemngiom with Arteril-Portl Venous Shunt Hemngiom with Cpsulr Retrction Hemngiom Developing in Anorml Liver Hemngiom in Ftty Liver Hemngiom in Liver Cirrhosis Assocition with Other Lesions Multiple Hemngioms Hemngiomtosis Focl Nodulr Hyperplsi Angiosrcom Atypicl Evolution Complictions Inflmmtory Process Ksch-Merritt Syndrome Intrtumorl Hemorrhge Hemoperitoneum Due to Spontneous Rupture of Hemngiom Dignostic Work Up 115 References 115 V. Vilgrin, MD Deprtment of Rdiology, Hospitl Beujon, Avenue Du Generl Leclerc 100, Clichy, Frnce G. Brnctelli, MD Deprtment of Rdiology, Policlinico Universitrio, Vi del Vespro 127, Plermo, Itly 8.1 Introduction Hemngiom is the most common enign heptic tumor. The prevlence of hemngiom in the generl popultion rnges from 1% 2% to 20% (Semelk nd Sofk 1997). The femle-to-mle rtio vries from 2:1 to 5:1. They occur t ll ges. The vst mjority of hemngioms remin cliniclly silent. Few ptients re symptomtic due to mss lesion, complictions or compression of djcent structures. Most of these symptoms re oserved in lrge hemngioms. The nturl history of hemngioms is vrile: most of them remin stle, some my grow or involute. The role of sex hormones in cusing enlrgement during pregnncy or recurrence is disputed. Hemngioms re usully solitry, less thn 5 cm in size nd pper s well-delineted lesions of red color tht prtilly collpse on sectioning. A few re pedunculted. Gint hemngioms (often defined s 10 cm or lrger) re heterogeneous nd show vrying degrees of firosis nd clcifiction. Some hemngioms my ecome entirely firous. Microscopiclly, hemngioms re composed of lood-filled spces of vrile size nd shpe nd re lined y single lyer of flt endothelium. The sept etween the spces re often incomplete. Blood vessels nd rteriovenous shunting my e seen in lrge sept (Crig et l. 1988). 8.2 Sonogrphy The clssic sonogrphic ppernce of hemngiom is tht of n echogenic mss of uniform-density, less thn 3 cm in dimeter with coustic enhncement nd shrp mrgins (Fig. 8.1). A hypoechoic center my e present. Typiclly hemngioms do not hve hypoechoic hlo (Bree et l. 1987). Liver hemngioms my present n typicl pttern on sonogrphy, usully if lrger thn 3 cm, ppering hypo- or isoechoic.

2 102 V. Vilgrin nd G. Brnctelli c Fig. 8.1 c. Typicl hemngiom t US nd CT. Ultrsonogrphy demonstrtes the hemngiom s hyperechoic focus ner the diphrgm. Nonenhnced CT section shows 2-cm lesion in the right loe of the liver tht is isottenuting to the ort. c On portl venous phse the lesion demonstrtes centripetl enhncement tht is isottenuting to the heptic vessels On color Doppler no vsculr pttern is identified ecuse intrlesionl flows re too slow to e reveled ut few peripherl flow signls my e seen (Tno et l. 1997). Power Doppler is more sensitive in reveling venous flows within hemngioms. Recent ppers hve highlighted the potentil of contrst enhnced hrmonic ultrsound (US) to chrcterize liver lesions. In hemngioms, the sence of intrtumorl vessels in the rteril phse nd peripherl nodulr enhncement in the portl phse re the most typicl ptterns nd were oserved in 76% nd 88%, respectively (Fig. 8.2) (Isozki et l. 2003). The sensitivity, specificity, nd ccurcy of dignosis sed on this comintion of enhncement pttern were 88%, 99%, nd 98% (Isozki et l. 2003). Peripherl gloulr enhncement in the portl phse nd isoechoic pttern on lte phse re lso oserved in most typicl hemngioms lrger thn 3 cm (Qui et l. 2002). 8.3 Computed Tomogrphy Strict criteri for the dignosis of hemngiom were descried efore the most recent technicl dvnces in computed tomogrphy (CT). These criteri were: Low ttenution on non-contrst CT Peripherl enhncement of the lesion followed y centrl enhncement on contrst CT Contrst enhncement of the lesion on delyed scns (Freeny nd Mrks 1986)

3 Liver Hemngiom 103 c Fig. 8.2 d. Typicl hemngiom t contrst enhnced US. Olique scending right sucostl seline imge in 63-yerold mn shows hypo-isoechoic lesion in the right liver. On the olique scending right sucostl imge otined in the rteril phse (25 s fter SonoVue injection), the lesion shows peripherl gloulr enhncement. c,d In the portl-venous nd delyed phses (60 s nd 120 s fter SonoVue injection, respectively) progressive ut incomplete centripetl fill-in is depicted. (Courtesy of Brtolott) d These criteri hve een updted with the helicl CT technique nd the multiphsic exmintion. Three-phse helicl CT is the most suitle technique. Presence of peripherl puddles t rteril phse hs sensitivity of 67%, specificity of 99%, nd positive predictive vlue of 86% for hemngiom (Nino- Murci et l. 2000). In series of 100 focl liver lesions, the only flse positive cse (lesion with peripherl puddles) ws melnom metstsis (Nino-Murci et l. 2000). With triphsic spirl CT, results re even etter for chrcteriztion of liver hemngiom. In series of 375 liver lesions, 86% (51/59) of the hemngioms hd peripherl nodulr enhncement of vsculr ttenution on rteril nd portl phse imging nd were hyperttenuting with possile centrl hypottenution or isottenution to vsculr spce in the equilirium phse (vn Leeuwen et l. 1996). In this series, there were no flse-positive cses. Conversely 13.6% of the hemngioms were typicl: hypottenuting on ll

4 104 V. Vilgrin nd G. Brnctelli phses or hypottenuting on oth rteril nd portl venous phses nd hyperttenuting in the equilirium phse, which proly correspond to firosed hemngioms (vn Leeuwen et l. 1996). One of the hllmrks of liver hemngioms is the isottenution with the rteril system (Fig. 8.1) (vn Leeuwen et l. 1996). Among the hemngioms, those which re the most difficult to chrcterize re lesions smller thn 3 cm, ecuse they my not demonstrte nodulr enhncement ut often enhnce homogeneously during the heptic rteril or portl venous phse (Fig. 8.3) (Kim et l. 2001). Kim et l. (2001) hs compred smll heptic hemngioms with hypervsculr mlignnt tumors nd hs shown tht t rteril phse CT, enhncement similr to ortic enhncement ws oserved in 19% 32% of hemngioms nd 0% 2% of mlignnt tumors; gloulr enhncement in 62% 68% nd 4% 12%, respectively. At portl venous phse, enhncement similr to lood pool enhncement ws oserved in 43% 54% hemngioms nd 4% 14% of mlignnt tumors; gloulr enhncement in 46% 49% nd 0% 2%, respectively (Kim et l. 2001). So, smll hemngioms frequently show typicl ppernces t CT resulting in decrese in sensitivity compred to lrger hemngioms ut specificity remins high. 8.4 Mgnetic Resonnce Two mjor ppers pulished in 1985 in the rdiologic literture hve underlined the potentil impor- c Fig. 8.3 c. Cpillry hemngiom with rterioportl shunt. Nonenhnced CT section shows 2-cm lesion tht is isottenuting to the ort in the right liver. On heptic rteril phse imge the lesion demonstrtes right uniform enhncement lmost isodense with the ort. Note the wedge-shped homogeneous hyperttenuting re djcent to the tumor, due to n rterioportl shunt. c Portl venous phse imge shows tht the hemngiom remins isodense to the ort nd heptic veins. The rterioportl shunt is no longer seen

5 Liver Hemngiom 105 tnce of mgnetic resonnce (MR) imging in the chrcteriztion of liver hemngioms (Iti et l. 1985; Strk et l. 1985). These ppers hve shown tht: Most hemngioms hve homogeneous ppernce nd smooth, well defined mrgins (Strk et l. 1985). Hemngioms hve significntly greter contrst-to-noise rtio thn cncer, especilly on long T2-weighted sequences (Strk et l. 1985). MR imging detects more hemngioms thn ny other technique (Strk et l. 1985). MR llows detection of lmost ll hemngioms over 1 cm in dimeter with 90% sensitivity, 92% specificity, nd n overll ccurcy of 90% (Iti et l. 1985; Strk et l. 1985). Both reports nd n editor s note emphsized the role of T2-weighted sequences nd suggested tht MR imging my ecome the procedure of choice for distinguishing liver hemngioms from liver cncer. Mny other ppers were pulished fterwrds discussing the role of low vs high field strengths, conventionl spin-echo (SE) T2-weighted imging vs fst imging techniques, fst SE imging with nd without ft suppression nd seril gdoliniumenhnced grdient echo (GE) imges (Soyer et l. 1997). The routine MR protocol for chrcterizing liver lesions includes grdient echo (GE) T1-weighted sequence, fst spin-echo (FSE) T2-weighted sequence preferly with ft suppression technique (ecuse it increses the contrst to noise rtio of liver hemngioms) nd gdolinium-enhnced triphsic dynmic GE imges (which my e cquired in 2D or in 3D). The clssicl ppernce of liver hemngioms is tht of hypointense lesion on T1-weighted sequences nd strongly hyperintense lesion on hevily T2-weighted sequences with light ul pttern (Fig. 8.4). This strong hypersignl on T2 is due to long T2 vlues (greter thn 88 ms). Numerous rticles hve ttempted to determine cut-off T2 vlue llowing discrimintion etween hemngioms nd mlignnt tumors. However, in most of the centers, the lesion chrcteriztion is otined with qulittive ssessment nd rrely with quntittive mesures (McFrlnd et l. 1994). More recently, other sequences hve een used to fcilitte rpid nd relile distinction etween hemngioms nd other lesions. Single-shot fst spin echo sequences re hlf-fourier technique tht enle cquisition of hevily T2-weighted imges within few seconds per slice nd re helpful for differentition etween liver lesions. By using short TE (90 ms) nd long TE ( ms) they my lso differentite hemngioms from cysts (Kiryu et l. 2002). True fst imging with stedy stte free precession is n ultrfst grdient echo sequence with lnced structure tht compenstes first-order phse shifts produced y flow. Echo nd repetition times re short. Imge contrst is relted to the T2*/T1 rtio. Comprison etween this sequence nd HASTE sequence hs shown tht distinction etween hemngioms nd liver mlignncies ws more often correct with the lnced sequence (Numminen et l. 2003). Tody, gdolinium chelte dministrtion with dynmic seril postcontrst MR imging is performed in ll cses nd is n nlogous technique to multiphsic contrst-enhnced CT. Hemngioms hve the following fetures: Peripherl hyperintense nodules with non-intct ring immeditely fter contrst dministrtion Progressive centripetl enhncement tht is most intense t 90 s Undulting nodulr contour of the inner ring mrgin Persistent homogeneous enhncement without heterogeneous or peripherl wshout (Semelk et l. 1994) Most of the medium (1.5 5 cm), nd lrge hemngioms (>5 cm) hd initil peripherl nodulr enhncement wheres uniform enhncement ws oserved in 35 of 81 smll lesions in Semelk s pper (Semelk et l. 1994). Interestingly, the rpid enhncing hemngioms tend to e hypoechoic on sonogrphy wheres lesions tht re slow-enhncing tend to e hyperechoic (Yu et l. 1998). Rpid-enhncing hemngioms my mimic other lesions t the rteril phse such s heptocellulr tumors or hypervsculr metstses (Fig. 8.5). However, most of them show hyperintense complete fill-in in the equilirium phse nd very high signl intensity with T2-weighted sequences (Kto et l. 2001). Therefore, comintion of T2-weighted imges with seril dynmic postgdolinium MR sequences is relile imging modlity for the dignosis of hemngioms.

6 106 V. Vilgrin nd G. Brnctelli c d e Fig. 8.4 e. Typicl hemngiom t MR imging. T2-weighted ft suppressed fst spin-echo MR imge shows hemngiom in the right liver with high signl intensity. T1-weighted grdient-echo ft-suppressed MR imge shows heptic hemngiom to e hypointense to surrounding liver prenchym. c Gdolinium-enhnced T1-weighted ft-suppressed grdientecho MR imge otined during rteril phse shows nodulr peripherl enhncement of hemngiom. d Gdolinium-enhnced T1-weighted ft-suppressed grdient-echo MR imge otined during portl venous phse shows centripetl filling of hemngiom. e Delyed-phse (5 minutes) gdolinium-enhnced T1-weighted ft-suppressed grdient-echo MR imge shows hemngiom lmost completely filled with contrst mteril

7 Liver Hemngiom 107 c Fig. 8.5 c. Cpillry flsh-filling hemngiom in cirrhotic liver. Nonenhnced trnsverse CT. The hemngiom is sucpsulr nd isottenuting to lood. Heptic rteril phse imge t the sme level. The hemngiom enhnces homogeneously nd eqully compred with splenic rtery. c On portl venous phse the lesion remins isottenuting to vessels, finding tht confirm lood-pool chrcteristics for the lesion. The lck of contrst mteril wshout in the portl venous phse llows differentition of cpillry hemngiom from heptocellulr crcinom in this cirrhotic liver 8.5 Scintigrphy 99m Tc-pertechnette-leled red lood cell scintigrphy is reltively specific exmintion for identifying hemngioms. Using this method, there is decresed ctivity on erly dynmic imges nd incresed ctivity on delyed lood pool imges. Comprison etween 99m Tc-pertechnette-leled red lood cell single-photon emission CT (SPECT) nd MR imging hs shown tht MR hd higher sensitivity nd specificity thn SPECT, especilly for lesions less thn 2 cm in dimeter (Birnum et l. 1990). 8.6 Percutneous Biopsy Liver hemngiom hs een considered contrindiction to needle iopsy for mny yers ecuse of the high risk of hemorrhge. Recently, severl series of percutneous iopsy in liver hemngioms hve een reported nd the contrindictions should e reconsidered. No serious complictions were oserved in two lrge series: one in 47 iopsy specimens otined using core-needle iopsy nd one in 114 ptients hving fine-needle spirtion iopsy (Heilo nd Stenwig 1997; Cldironi et l. 1998). In the ltter, two minor ccidents were oserved due to profuse leeding of gint hemngiom nd resolved with medicl cre. However, s in other tumors, cuff

8 108 V. Vilgrin nd G. Brnctelli of norml heptic prenchym should e interposed etween the cpsule nd the mrgin of hemngiom. Indictions of percutneous iopsy should e restricted to typicl cses despite comintion of imging modlities. Sensitivity nd overll ccurcy re reported in more thn 90% (Cldironi et l. 1998; Nkizumi et l. 1990). Interestingly, oth core-needle iopsy nd fineneedle spirtion iopsy re useful in dignosing liver hemngiom. 8.7 Atypicl Ptterns Hemngiom with Echoic Border An typicl ut suggestive ppernce of hemngioms t US is the following: the lesion hs n echoic order, which is seen s thick echoic rind or thin echoic rim (Moody nd Wilson 1993). Unlike typicl hemngioms, this type of hemngiom hs n internl echo pttern tht is t lest prtilly hypoechoic. The centrl low echogenicity is ssumed to correspond to previous hemorrhgic necrosis, scrring, or myxomtous chnges. Although, the rel percentge is unknown, some uthors hve reported tht 40% of ll hemngioms could hve this typi (Moody nd Wilson 1993) Lrge, Heterogeneous Hemngiom Lrge hemngioms re often heterogeneous (Ymshit et l. 1994). They re termed gint hemngioms when they exceed 4 cm in dimeter (Nelson nd Chezmr 1990; Vlls et l. 1996). However, some uthors define gint hemngioms s lesions greter thn 6 cm or 12 cm in dimeter (Choi et l. 1989; Dnet et l. 2003). Lrge hemngioms my e responsile for liver enlrgement nd dominl discomfort. At US, lrge hemngioms often pper heterogeneous. On non-enhnced CT scns, lesions pper hypottenuting nd heterogeneous with mrked centrl res of low ttenution. After intrvenous dministrtion of contrst mteril, the typicl erly, peripherl, gloulr enhncement is oserved. However, during the venous nd delyed phses, the progressive centripetl enhncement of the lesion, lthough present, does not led to complete filling (Fig. 8.6). At MR imging, T1-weighted sequences show shrply mrginted, hypointense mss with cleft-like re of lower intensity nd sometimes with hypointense internl sept. T2-weighted imges show mrkedly hyperintense cleft-like re nd some hypointense internl sept within hyperintense mss. The enhncement is equivlent to tht seen t CT, with incomplete filling of the lesion; the cleft-like re remins hypointense, s do the internl sept (Fig. 8.7) (Choi et l. 1989). The MR imging findings of gint hemngioms re closely correlted with the mcroscopic ppernce, which demonstrtes chnges such s hemorrhge, thromosis, extensive hyliniztion, liquefction, nd firosis. The centrl cleft-like re my e due to cystic degenertion, liquefction or myxoid tissue (Choi et l. 1989; Dnet et l. 2003). Modifictions of internl components such s thromosis nd hemorrhge my induce compression of iliry nd vsculr structures (Coumrs et l. 2002) Rpidly Filling Hemngiom Rpidly filling hemngioms re not very frequent (16% of ll hemngioms). However, rpid filling seems to occur significntly more often in smll hemngioms (42% of hemngioms <1 cm in dimeter) (Figs. 8.3, 8.5) (Hnfus et l. 1995). CT nd MR imging show prticulr enhncement pttern: immedite homogeneous enhncement t rteril-phse CT or contrst-enhncement T1-weighted MR imging (Figs. 8.3, 8.5) (Semelk nd Sofk 1997). This feture mkes differentition from other hypervsculr tumors difficult. T2- weighted imges my e helpful, ut hypervsculr tumors such s islet cell metstses re lso hyperintense on such imges. Accurte dignosis is mde with delyed-phse CT or MR imging ecuse hemngioms remin hyperttenuting or hyperintense, wheres hypervsculr metstses do not (Figs. 8.3, 8.5). Another importnt finding in dignosis of hemngiom is ttenution equivlent to tht of the ort during ll phses of CT (Figs. 8.3, 8.5) (Quinn nd Benjmin 1992). At Doppler US, unusul rteril flow my e present. Becuse histopthologic confirmtion is usully not performed, the mechnism of the enhncement is not clerly understood; however, the difference in enhncement ptterns my e due to difference in the size of the lood spces. It is likely tht the smller

9 Liver Hemngiom 109 c Fig. 8.6-c. Gint cvernous hemngioms t CT. Nonenhnced CT section demonstrtes mssive hemngiom tht replces the right nd cudte loe of the liver. Clcifictions re noted in lrge hypottenuting centrl scr. Peripherl nodulr enhncement without complete filling is demonstrted on the postcontrst imge. A smller hemngiom is seen in the IV liver segment. c Multiplnr reformtion on coronl olique plne demonstrtes the gross clcifictions nd nodulr enhncement of the lesion Fig. 8.7,. Gint cvernous hemngioms t MR. Ft-suppressed T1-weighted grdient-echo MR imge shows gint cvernous hemngiom replcing the right liver with nodulr, centripetl, cloud-like enhncement. T2-weighted ft suppressed fst spin-echo MR imge shows hemngiom to e of high signl intensity to norml liver. The centrl hyperintense re corresponds to centrl scr. Multiple hypointense liner elements corresponding to internl firotic sept re noted within the lesion. Numerous other hyperintense lesions, corresponding to smller hemngioms, re seen in the left loe of the liver

10 110 V. Vilgrin nd G. Brnctelli the lesion, the more rpid is the spred of contrst mteril within it (Hnfus et l. 1995). This theory could explin the high proportion of smll hemngioms with rpid nd complete filling Very Slow Filling Hemngiom They pper s hypottenuting lesions on multiphsic exmintion or they hve tiny enhncing dots tht do not progress to the clssic gloulr enhncement (Fig. 8.8). Their incidence is estimted t etween 8% 16% of cses. They re prolemtic in ptients with mlignncy (Jng et l. 2003) Clcified Hemngiom Although hemngioms in the soft tissue, gstrointestinl trct, retroperitoneum, nd medistinum my show clcifictions (phleoliths, which re pthognomonic for the tumor), heptic hemngioms rrely demonstrte clcifictions (Drlk et l. 1990; Sctrige et l. 1983). Clcified hemngioms re mostly found incidentlly. Clcifictions my occur in the mrginl or centrl portion of the lesion (Mitsudo et l. 1995). A prticulr pttern consists of multiple spotty clcifictions, which correspond to phleoliths. However, lrge, orgnized clcifictions re lso possile. Some clcified hemngioms my demonstrte poor enhncement, especilly t CT (Mitsudo et l. 1995). The finding of nonenhncing heptic tumor with clcifictions should not preclude the dignosis of hemngiom. High signl intensity in non-clcified res of the lesion on T2-weighted MR imges cn help in dignosis Hylinized Hemngiom Hylinized heptic hemngioms re rre (Cheng et l. 1995; Tung et l. 1994). Some uthors hve suggested tht hylinized hemngioms represent n end stge of hemngiom involution. Such hemngioms do not demonstrte ny prticulr symptoms. Hyliniztion of hemngiom chnges its rdiologicl fetures, thus mking dignosis efore iopsy virtully impossile. Hylinized hemngioms show only slight high signl intensity on T2-weighted MR imges (Cheng et l. 1995). Moreover, there is lck of erly enhncement on dynmic contrst-enhnced imges. Slight peripherl enhncement my occur in the lte phse (Cheng et l. 1995). MR imging does not llow differentition of hylinized hemngioms from mlignnt heptic tumors. Pthologic exmintion revels extensive firous tissue nd olitertion of vsculr chnnels (Cheng et l. 1995). Fig. 8.8,. Hemngiom ssocited with focl nodulr hyperplsi. Heptic rteril-phse imge shows two focl nodulr hyperplsi lesions with strong nd homogeneous hyperttenution in comprison to djcent liver prenchym. A centrl scr is noted in the lrgest lesion. Hemngiom shows nodulr peripherl enhncement. On portl venous-phse imge the focl nodulr hyperplsi lesions re isottenuting to liver, while hemngiom shows progressive nodulr, centripetl enhncement tht is unusully slow

11 Liver Hemngiom Cystic or Multiloculr Hemngiom Cvernous hemngioms with lrge centrl cvity tht contins fluid re very rre. To our knowledge, only one hemngiom with multiloculr cystic component hs een reported in the literture (Hihr et l. 1990). This entity does not demonstrte ny prticulr symptoms. Definite dignosis of such hemngioms with imging is difficult. This typi my e due to cystic degenertion cused y centrl thromosis nd hemorrhge Hemngiom with Fluid Fluid Level Fluid fluid levels within hemngioms re very rre. To our knowledge, only three rticles on this entity hve een pulished (Azencot et l. 1993; Iti et l. 1987; Soyer et l. 1998). The ptient my present with dominl pin. US shows hyperechoic or hypoechoic pttern. The fluid fluid level is not seen t US (Azencot et l. 1993; Soyer et l. 1998). CT nd especilly MR imging esily demonstrte this feture (Iti et l. 1987) Hemngiom with Arteril-Portl Venous Shunt Arteril-portl venous shunts re minly ssocited with heptic mlignncy ut cn lso e seen in enign liver msses, in prticulr hemngioms (Winogrd nd Pluinsks 1977; Shimd et l. 1994). This entity is usully symptomtic. An rteril-portl venous shunt cn e detected with helicl CT or dynmic contrst-enhnced MR imging. The findings consist of erly prenchyml enhncement ssocited with erly filling of the portl vein (Hnfus et l. 1995). Arterio-portl shunts re found in 25% of hemngioms. They re not relted to the lesion size ut they re more frequently seen in hemngioms with rpid enhncement (Fig. 8.3) (Kim et l. 2001) Hemngiom with Cpsulr Retrction Cpsulr retrction is usully ssocited with mlignnt tumors such s cholngiocrcinom, epithelioid hemngioendotheliom, or metstses. This finding is very rre in enign liver tumors nd hs een descried in very few hemngioms (Fig. 8.9) (Yng et l. 2001) Pedunculted Hemngiom Pedunculted hemngioms re very rre. To our knowledge, only two cses hve een reported in the literture (Ellis et l. 1985; Trn-Minh et l. 1991). They cn e symptomtic or complicted y sucute torsion nd infrction. At US, the origin of the lesion my e difficult to recognize. The lesion cn e ttched to the liver y thin pedicle, which is nerly undetectle t imging. Multiplnr reconstruction of CT scns nd coronl or sgittl MR imging cn e helpful. At CT nd MR imging, the dignosis is mde y demonstrting the typicl enhncement pttern nd the typicl signl intensities on oth T1- nd T2-weighted imges. Complicted pedunculted hemngioms must e resected. Fig Hemngiom with cpsulr retrction. Portl-phse CT demonstrtes lrge mss in the left loe of the liver with centrl hypottenuting scr nd ssocited cpsulr retrction

12 112 V. Vilgrin nd G. Brnctelli 8.8 Hemngiom Developing in Anorml Liver Hemngiom in Ftty Liver Diffuse ftty infiltrtion of the liver is common finding nd my chnge the typicl ppernces of lesions, mking them more difficult to chrcterize t imging. At US, hemngiom my pper slightly hyperechoic, isoechoic, or hypoechoic reltive to ftty liver (Mrsh et l. 1989). Posterior coustic enhncement is usully oserved. At non-enhnced CT, the lesion my e hyperttenuting reltive to the liver or my not seen (Fig. 8.10). Contrst-enhnced CT shows peripherl enhncement nd delyed filling, n ppernce similr to tht of hemngiom in norml liver (Freeny nd Mrks 1986). However, t rteril-phse imging, the hemngiom my e isottenuting reltive to the liver. MR imging is more helpful thn CT nd llows relile detection nd differentition of hemngioms from other heptic msses (Fig. 8.11) (Strk et l. 1985). Hemngioms my lso e ccompnied y focl spred zone s seen in mlignnt tumors in ftty liver (Jng et l. 2003) Hemngiom in Liver Cirrhosis With progressive cirrhosis, hemngioms re likely to decrese in size nd ecome more firotic nd difficult to dignose rdiologiclly (Brnctelli et l. 2001). 8.9 Assocition with Other Lesions Multiple Hemngioms Hemngioms re multiple in 10% of cses (Ishk nd Rin 1975). Multiple hemngioms generlly consist of few scttered lesions (Ymshit et l. 1994). They often hve typicl imging fetures Hemngiomtosis Hemngioms, even gint ones, re usully well defined (Vlls et l. 1996). In rre cses, the lesion my e lrge nd ill defined, replcing lmost the whole heptic prenchym. This entity is seen more often Fig. 8.10,. Hemngiom in ftty liver t CT. Nonenhnced CT scn shows hyperttenuting lesion in hypottenuting ftty liver prenchym. Portl-phse CT scn shows nodulr centripetl enhncement of the lesion

13 Liver Hemngiom 113 c d Fig d. Hemngiom in ftty liver t MR imging. T2-weighted ft suppressed fst spin-echo MR imge shows hemngiom with signl intensity lmost s strong s tht of the cererospinl fluid. Gdolinium-enhnced T1-weighted grdient-echo MR imge otined during portl venous phse shows nodulr peripherl enhncement of hemngiom. c Axil T1-weighted in-phse grdient echo imge shows norml intermedite to high signl intensity liver in comprison to spleen. The hemngiom is seen s hypointense to surrounding liver. d Corresponding xil T1-weighted opposed-phse grdient echo imge shows loss of signl intensity of the liver compred with the spleen, representing heptic stetosis. Hemngiom is hyperintense to liver in infnts thn in dults nd my e ssocited with crdic filure nd high mortlity. In dults, hemngiomtosis cn e symptomtic Focl Nodulr Hyperplsi Assocition of heptic hemngiom nd focl nodulr hyperplsi is quite frequent (23% of cses) nd not fortuitous (Fig. 8.8) (Mthieu et l. 1989). It hs lso een suggested tht the ssocition is more frequent in cses of multiple focl nodulr hyperplsi (33%) (Vilgrin et l. 2003). Focl nodulr hyperplsi is considered to e hyperplstic response due to focl incresed rteril flow in the heptic prenchym nd, like hemngiom, is thought to hve vsculr origin. When the tumors hve typicl imging fetures, the dignosis cn e mde with confidence.

14 114 V. Vilgrin nd G. Brnctelli Angiosrcom To our knowledge, there is only one report of mlignnt trnsformtion of heptic hemngiom in the literture (Bertrnd et l. 1980). Another report descried cvernous hemngiom surrounded y ngiosrcom, nd the uthors rised the hypothesis of mlignnt trnsformtion of hemngiom (Tohme et l. 1991) Atypicl Evolution Most hemngioms remin stle in size or demonstrte miniml increse in dimeter over time (Nghiem et l. 1997; Tkysu et l. 1990). Very few oservtions of significnt enlrgement of hemngiom hve een reported (Schwrtz nd Husser 1987; Nghiem et l. 1997; Tkysu et l. 1990). They include cses of enlrgement during pregnncy nd during estrogen use. Enlrged hemngioms cn e symptomtic or my mnifest s n dominl mss or pin. The US, CT, nd MR imging fetures re identicl to those of typicl hemngioms. The mechnism of enlrgement is elieved to e vsculr ectsi (Fouchrd et l. 1994). A role for estrogen in hemngiom enlrgement is suspected ut hs never een proved (Schwrtz nd Husser 1987; Fouchrd et l. 1994). Despite the growth of the lesion, if imging fetures re chrcteristic of hemngiom, the dignosis cn still e mde confidently with imging Complictions The overll compliction rte vries from 4.5% to 19.7% (Freeny et l. 1979). Complictions re mostly oserved in lrge hemngioms nd cn e divided into ltertions of internl rchitecture such s inflmmtion; cogultion, which could led to systemic disorders; hemorrhge, which cn cuse hemoperitoneum, volvulus, nd compression of djcent structures Inflmmtory Process Some cses of inflmmtory processes complicting gint hemngioms hve een reported (Tkysu et l. 1990). The prevlence is proly underestimted. Signs nd symptoms of n inflmmtory process include low-grde fever, weight loss, dominl pin, ccelerted erythrocyte sedimenttion rte, nemi, thromocytosis, nd incresed firinogen level. The imging fetures re those of gint hemngiom. Histologicl signs of inflmmtion my not e detected. A possile explntion is the relese of immune meditors y heptic endothelil cells lining the hemngiom. Clinicl nd lortory normlities my dispper fter surgicl excision of the hemngiom Ksch-Merritt Syndrome Ksch-Merritt syndrome is rre compliction of heptic hemngioms in dults. It is cogulopthy consisting of intrvsculr cogultion, clotting, nd firinolysis within the hemngiom (Aout et l. 1994). The initilly loclized cogulopthy my progress to secondry incresed systemic firinolysis nd thromocytopeni, leding to ftl outcome in 20% 30% of ptients (Mceyko nd Cmis 1991) Intrtumorl Hemorrhge Intrtumorl hemorrhge is rrely encountered in heptic hemngioms. It cn occur spontneously or fter nticogultion therpy. The symptoms consist of cute-onset vomiting nd epigstric pin (Grhm et l. 1993). The leeding is suggested y intrtumorl high ttenution on non-enhnced CT scns nd high signl intensity on T1-weighted MR imges. When the typicl enhncement fetures of hemngiom re present in ssocition with mrked high signl intensity on T2-weighted MR imges, the dignosis cn e mde. If not, histopthologicl exmintion llows correct dignosis.

15 Liver Hemngiom Hemoperitoneum Due to Spontneous Rupture of Hemngiom Spontneous rupture of hemngiom is unusul. Clinicl symptoms include cute dominl pin. Imging procedures revel hemoperitoneum. Intrperitonel clotting my e seen djcent to the leeding hemngiom. MR imging is very sensitive in detection of leeding y showing high signl intensity on T1-weighted imges. Angiogrphy cn e useful for dignosis, nd emoliztion cn e performed, thus llowing plnned heptic resection (Soyer nd Levesque 1995) Dignostic Work Up The dignostic evlution of hemngioms vries with different clinicl nd imging scenrios (Nelson nd Chezmr 1990). Typicl ppernce of hemngiom t US imging does not require ny work up in ptient with no mlignncy or chronic liver disese. Conversely, in ptients with typicl imging or t high risk for developing heptic mlignncies, dignostic confirmtion is mndtory. Although overll ccurcy of CT for dignosing hemngiom is high, MR imging is the recommended modlity with oth T2 nd postgdolinium informtion. If the dignosis remins inconclusive, then percutneous iopsy is indicted. In conclusion, rdiologists hve to fce two prolems in dignosing liver hemngioms. First, to differentite typicl hemngioms from other liver lesions, especilly liver mlignncies. The impct is so importnt tht we should keep in mind getting 100% specificity for hemngioms which implies tht doutful cses should not e considered s hemngioms. Flse positive hemngioms re much more drmtic thn flse negtive cses. Second, to recognize typicl hemngioms. Although typicl hemngioms re rre, mny rdiologists will encounter typicl findings due to the high prevlence of heptic hemngioms. In some cses, such s lrge heterogeneous hemngioms, clcified hemngioms, pedunculted hemngioms, or hemngioms developing in diffuse ftty liver, specific dignosis cn e estlished with imging, especilly MR imging. However, in other typicl cses, the dignosis will remin uncertin t imging, nd these cses will require histopthologicl exmintion. References Aout I, Cpdeville J, Bernrd P, et l (1994) Hémngiome héptique gént non résécle et syndrome de Ksch- Merritt. Rev Med Interne 15: Azencot M, Soyer P, Lissy J-P, et l (1993) Niveux liquideliquide dns des ngiomes multiples du foie: spect en IRM et en TDM. Rev Im Med 5: Bertrnd L, Puyeo J, Pges A, et l (1980) Hémngiosrcome du foie secondire à un ngiome cverneux clcifié: mort en cogulopthie de consommtion. Ann Gstroenterol Heptol 16:19 27 Birnum BA, Weinre JC, Megiow AJ (1990) Definitive dignosis of heptic hemngioms: MR vs Tc-99m leled red lood cell SPECT. Rdiology 176: Brnctelli G, Federle MP, Blchr A, et l (2001) Hemngiom in the cirrhotic liver: dignosis nd nturl history. Rdiology 219:69 74 Bree RL, Schw RE, Glzer GM, et l (1987) The vried ppernces of heptic cvernous hemngioms with sonogrphy, computed tomogrphy, mgnetic resonnce imging nd scintigrphy. Rdiogrphics 7: Cldironi MW, Mzzucco M, Aldinio MT, et l (1998) Echoguided fine-needle iopsy for the dignosis of heptic ngiom. A report on 114 cses. Minerv Chir 53: Cheng HC, Tsi SH, Ching JH, et l (1995) Hylinized liver hemngiom mimicking mlignnt tumor t MR imging. AJR Am J Roentgenol 165: Choi BI, Hn MC, Prk JH, et l (1989) Gint cvernous hemngiom of the liver: CT nd MR imging in 10 cses. AJR Am J Roentgenol 152: Coumrs M, Wendum D, Monnier-Cholley L, et l (2002) CT nd MR imging fetures of pthologiclly proven typicl gint hemngiom of the liver. AJR Am J Roentgenol 179: Crig JR, Peters RL, Edmondson HA (1988) Tumors of the liver nd intrheptic ile ducts. AFIP, Wshington, pp Dnet IM, Semelk, RC, Brg L, et l (2003) Gint hemngiom of the liver: MR imging chrcteristics in 24 ptients. Mgn Res Img 21: Drlk JJ, Moshowitz M, Kttn KR (1990) Clcifictions in the liver. Rdiol Clin North Am 18: Ellis JV, Slzr JE, Gvnt ML (1985) Pedunculted heptic hemngiom: n unusul cuse for nteriorly displced retroperitonel ft. J Ultrsound Med 4: Fouchrd I, Rosenu L, Clès P, et l (1994) Survenue d hémngiomes héptiques u cours de l grossesse. Gstroenterol Clin Biol 18: Freeny PC, Mrks WM (1986) Heptic hemngiom: dynmic olus CT. AJR Am J Roentgenol 147: Freeny PC, Vimont TR, Brnett DC (1979) Cvernous hemngiom of the liver: ultrsonogrphy, rteriogrphy, nd computed tomogrphy. Rdiology 132: Grhm E, Cohen AW, Soulen M, et l (1993) Symptomtic liver hemngiom with intr-tumor hemorrhge treted y ngiogrphy nd emoliztion during pregnncy. Ostet Gynecol 81: Hnfus K, Ohshi I, Himeno Y, et l (1995) Heptic hemngiom: findings with two-phse CT. Rdiology 196: Heilo A, Stenwig AE (1997) Liver hemngiom: US-guided 18- Guge core-needle iopsy. Rdiology 204: Hihr T, Arki T, Ktou K, et l (1990) Cystic cvernous hemngiom of the liver. Gstrointest Rdiol 15:

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17 Liver Hemngiom 117 Vilgrin V, Uzn F, Brnctelli G, et l (2003) Prevlence of heptic hemngiom in ptients with focl nodulr hyperplsi: MR imging nlysis. Rdiology 229:75 79 Winogrd J, Pluinsks J (1977) Arteril-portl venous shunting in cvernous hemngiom of the liver. Rdiology 122: Ymshit Y, Htnk Y, Ymmoto H, et l (1994) Differentil dignosis of focl liver lesions: role of spin-echo nd contrst-enhnced dynmic MR imging. Rdiology 193:59 65 Yng DM, Yvon MH, Kim HS, et l (2001) Cpsulr retrction in heptic gint hemngiom: CT nd MR fetures. Adom Imging 26:36 38 Yu JS, Kim MJ, Kim KW et l (1998) Heptic cvernous hemngiom: sonogrphic ptterns nd speed of contrst enhncement on multiphse dynmic MR imging. AJR Am J Roentgenol 171: