Liver Hemangioma 101 8 Liver Hemangioma Valérie Vilgrain and Giuseppe Brancatelli CONTENTS 8.1 Introduction 8.1 Introduction 101 8.2 Sonography 101 8.3 Computed Tomography 102 Hemangioma is the most common benign hepatic 8.4 Magnetic Resonance 104 tumor. The prevalence of hemangioma in the general 8.5 Scintigraphy 107 population ranges from 1%–2% to 20% (Semelka and 8.6 Percutaneous Biopsy 107 Sofka 1997). The female-to-male ratio varies from 8.7 Atypical Patterns 108 2:1 to 5:1. They occur at all ages. The vast majority of 8.7.1 Hemangioma with Echoic Border 108 8.7.2 Large, Heterogeneous Hemangioma 108 hemangiomas remain clinically silent. Few patients 8.7.3 Rapidly Filling Hemangioma 108 are symptomatic due to a mass lesion, complications 8.7.4 Very Slow Filling Hemangioma 110 or compression of adjacent structures. Most of these 8.7.5 Calcifi ed Hemangioma 110 symptoms are observed in large hemangiomas. The 8.7.6 Hyalinized Hemangioma 110 natural history of hemangiomas is variable: most of 8.7.7 Cystic or Multilocular Hemangioma 111 8.7.8 Hemangioma with Fluid–Fluid Level 111 them remain stable, some may grow or involute. The 8.7.9 Pedunculated Hemangioma 111 role of sex hormones in causing enlargement during 8.7.10 Hemangioma with pregnancy or recurrence is disputed. Arterial-Portal Venous Shunt 111 Hemangiomas are usually solitary, less than 5 cm 8.7.11 Hemangioma with Capsular Retraction 111 in size and appear as well-delineated lesions of red 8.8 Hemangioma Developing in Abnormal Liver 112 color that partially collapse on sectioning. A few are 8.8.1 Hemangioma in Fatty Liver 112 pedunculated. Giant hemangiomas (often defi ned as 8.8.2 Hemangioma in Liver Cirrhosis 112 10 cm or larger) are heterogeneous and show varying 8.9 Association with Other Lesions 112 degrees of fi brosis and calcifi cation. Some hemangio- 8.9.1 Multiple Hemangiomas 112 mas may become entirely fi brous. 8.9.2 Hemangiomatosis 112 8.9.3 Focal Nodular Hyperplasia 113 Microscopically, hemangiomas are composed of 8.9.4 Angiosarcoma 114 blood-fi lled spaces of variable size and shape and are 8.10 Atypical Evolution 114 lined by a single layer of fl at endothelium. The septa 8.11 Complications 114 between the spaces are often incomplete. Blood ves- 8.11.1 Infl ammatory Process 114 sels and arteriovenous shunting may be seen in large 8.11.2 Kasabach-Merritt Syndrome 114 Craig 8.11.3 Intratumoral Hemorrhage 114 septa ( et al. 1988). 8.11.4 Hemoperitoneum Due to Spontaneous Rupture of Hemangioma 115 8.12 Diagnostic Work Up 115 References 115 8.2 Sonography The classic sonographic appearance of hemangioma is that of an echogenic mass of uniform-density, less than 3 cm in diameter with acoustic enhancement and V. Vilgrain, MD sharp margins (Fig. 8.1). A hypoechoic center may be Department of Radiology, Hospital Beaujon, Avenue Du present. Typically hemangiomas do not have a hy- General Leclerc 100, 92118 Clichy, France Bree G. Brancatelli, MD poechoic halo ( et al. 1987). Liver hemangiomas Department of Radiology, Policlinico Universitario, Via del may present an atypical pattern on sonography, usually Vespro 127, 90127 Palermo, Italy if larger than 3 cm, appearing hypo- or isoechoic. 102 V. Vilgrain and G. Brancatelli a b Fig. 8.1a–c. Typical hemangioma at US and CT. a Ultra- sonography demonstrates the hemangioma as a hyperechoic focus near the diaphragm. b Nonenhanced CT section shows a 2-cm lesion in the right lobe of the liver that is isoattenuating to the aorta. c On portal venous phase the lesion demonstrates centripetal enhancement that is isoattenuating to the hepatic c vessels On color Doppler no vascular pattern is identifi ed isoechoic pattern on late phase are also observed because intralesional fl ows are too slow to be revealed in most atypical hemangiomas larger than 3 cm but few peripheral fl ow signals may be seen (Tano et (Quaia et al. 2002). al. 1997). Power Doppler is more sensitive in revealing venous fl ows within hemangiomas. Recent papers have highlighted the potential of contrast enhanced 8.3 harmonic ultrasound (US) to characterize liver le- Computed Tomography sions. In hemangiomas, the absence of intratumoral vessels in the arterial phase and peripheral nodu- Strict criteria for the diagnosis of hemangioma were lar enhancement in the portal phase are the most described before the most recent technical advances typical patterns and were observed in 76% and 88%, in computed tomography (CT). These criteria were: respectively (Fig. 8.2) (Isozaki et al. 2003). The sen- ț Low attenuation on non-contrast CT sitivity, specifi city, and accuracy of diagnosis based ț Peripheral enhancement of the lesion followed by on this combination of enhancement pattern were a central enhancement on contrast CT 88%, 99%, and 98% (Isozaki et al. 2003). Peripheral ț Contrast enhancement of the lesion on delayed globular enhancement in the portal phase and scans (Freeny and Marks 1986) Liver Hemangioma 103 a b c d Fig. 8.2a–d. Typical hemangioma at contrast enhanced US. a Oblique ascending right subcostal baseline image in a 63-year- old man shows a hypo-isoechoic lesion in the right liver. b On the oblique ascending right subcostal image obtained in the arterial phase (25 s after SonoVue injection), the lesion shows peripheral globular enhancement. c,d In the portal-venous and delayed phases (60 s and 120 s after SonoVue injection, respectively) a progressive but incomplete centripetal fi ll-in is depicted. (Courtesy of Bartolotta) These criteria have been updated with the heli- With triphasic spiral CT, results are even better for cal CT technique and the multiphasic examination. characterization of liver hemangioma. In a series of Three-phase helical CT is the most suitable technique. 375 liver lesions, 86% (51/59) of the hemangiomas had Presence of peripheral puddles at arterial phase has peripheral nodular enhancement of vascular attenua- a sensitivity of 67%, a specifi city of 99%, and a posi- tion on arterial and portal phase imaging and were hy- tive predictive value of 86% for hemangioma (Nino- perattenuating with possible central hypoattenuation Murcia et al. 2000). or isoattenuation to vascular space in the equilibrium In a series of 100 focal liver lesions, the only false phase (van Leeuwen et al. 1996). In this series, there positive case (lesion with peripheral puddles) was were no false-positive cases. Conversely 13.6% of the a melanoma metastasis (Nino-Murcia et al. 2000). hemangiomas were atypical: hypoattenuating on all 104 V. Vilgrain and G. Brancatelli phases or hypoattenuating on both arterial and por- globular enhancement in 62%–68% and 4%–12%, tal venous phases and hyperattenuating in the equi- respectively. At portal venous phase, enhancement librium phase, which probably correspond to fi brosed similar to blood pool enhancement was observed hemangiomas (van Leeuwen et al. 1996). in 43%–54% hemangiomas and 4%–14% of malig- One of the hallmarks of liver hemangiomas is nant tumors; globular enhancement in 46%–49% the isoattenuation with the arterial system (Fig. 8.1) and 0%–2%, respectively (Kim et al. 2001a). So, small (van Leeuwen et al. 1996). Among the hemangio- hemangiomas frequently show atypical appearances mas, those which are the most diffi cult to character- at CT resulting in a decrease in sensitivity compared ize are lesions smaller than 3 cm, because they may to larger hemangiomas but specifi city remains high. not demonstrate nodular enhancement but often en- hance homogeneously during the hepatic arterial or portal venous phase (Fig. 8.3) (Kim et al. 2001a). Kim et al. (2001a) has compared small hepatic hemangio- 8.4 mas with hypervascular malignant tumors and has Magnetic Resonance shown that at arterial phase CT, enhancement simi- lar to aortic enhancement was observed in 19%–32% Two major papers published in 1985 in the radio- of hemangiomas and 0%–2% of malignant tumors; logic literature have underlined the potential impor- a b Fig. 8.3a–c. Capillary hemangioma with arterioportal shunt. a Nonenhanced CT section shows a 2-cm lesion that is isoat- tenuating to the aorta in the right liver. b On hepatic arterial phase image the lesion demonstrates bright uniform enhance- ment almost isodense with the aorta. Note the wedge-shaped homogeneous hyperattenuating area adjacent to the tumor, due to an arterioportal shunt. c Portal venous phase image shows that the hemangioma remains isodense to the aorta and c hepatic veins. The arterioportal shunt is no longer seen Liver Hemangioma 105 tance of magnetic resonance (MR) imaging in the per slice and are helpful for differentiation between characterization of liver hemangiomas (Itai et al. liver lesions. By using a short TE (90 ms) and a long 1985; Stark et al. 1985). These papers have shown TE (600–700 ms) they may also differentiate heman- that: giomas from cysts (Kiryu et al. 2002). True fast im- ț Most hemangiomas have a homogeneous appear- aging with steady state free precession is an ultrafast ance and smooth, well defi ned margins (Stark et gradient echo sequence with a balanced structure al. 1985). that compensates fi rst-order phase shifts produced ț Hemangiomas have a signifi cantly greater con- by fl ow. Echo and repetition times are short. Image trast-to-noise ratio than cancer, especially on long contrast is related to the T2*/T1 ratio. Comparison T2-weighted sequences (Stark et al. 1985). between this sequence and HASTE sequence has ț MR imaging detects more hemangiomas than any shown that distinction between hemangiomas and other technique (Stark et al. 1985). liver malignancies was more often correct with the ț MR allows detection of almost all hemangiomas balanced sequence (Numminen et al.