You are in: eMedicine Specialties > Radiology > GASTROINTESTINAL Cavernous Hemangioma, LiverArticle Last Updated: Aug 29, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Srinivasa Prasad, MD, Associate Professor, Department of Radiology, Division of Abdominal Imaging and Intervention, University of Texas Health Science Center at San Antonio Srinivasa Prasad is a member of the following medical societies: American Roentgen Ray Society, Radiological Society of North America, and Society of Uroradiology Coauthor(s): Dushyant Sahani, MD, Clinical Instructor of Abdominal Radiology and Intervention, Harvard Medical School; Assistant Radiologist, Department of Abdominal Imaging and Intervention, Massachusetts General Hospital; Sanjay Saini, MD, Associate Professor, Department of Radiology, Harvard Medical School; Vice Chairman, Department of Radiology, Health System Affairs, Massachusetts General Hospital Editors: Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Udo P Schmiedl, MD, PhD, Clinical Professor, Department of Radiology, University of Washington; Consulting Staff, Swedish Medical Center, University of Washington Medical Center, Seattle Radiologists; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; John Karani, MBBS, FRCR, Consulting Staff, Department of Radiology, King's College Hospital, London Author and Editor Disclosure Synonyms and related keywords: hepatic cavernous hemangioma, hepatic hemangioma, hemangioma of the liver, giant hemangioma of the liver, primary liver tumor, focal nodular hyperplasia, Kasabach-Merritt syndrome INTRODUCTIONSection 2 of 11
  BackgroundCavernous hemangioma is the most common primary liver tumor; its occurrence in the general population ranges from 0.4-20%, as reported by Karhunen in an autopsy series.1 Cavernous hemangiomas arise from the endothelial cells that line the blood vessels and consist of multiple, large vascular channels lined by a single layer of endothelial cells and supported by collagenous walls. These tumors are frequently asymptomatic and incidentally discovered at imaging, surgery, or autopsy. Hemangiomas are uncommon in cirrhotic livers; the fibrotic process in cirrhotic liver may prohibit their development.2 Usually, cavernous hemangiomas occur as solitary lesions; however, they may be multiple in as many as 50% of patients.3 No lobar predilection exists, and the tumors may be associated with focal nodular hyperplasia.4 Hemangiomas typically measure less than 5 cm; those larger than 4-5 cm are sometimes called giant hemangiomas.5, 6 PathophysiologyThe natural history of liver hemangioma is not completely understood. Hemangiomas are probably congenital in origin, and hereditary factors may play a role in the pathogenesis of some familial forms of these tumors. Although the growth of hemangiomas is reported in the literature, ectasia is believed to contribute to lesion enlargement.7 Moreover, according to the findings in a study by Brancatelli et al, hemangiomas may become fibrotic and shrink in patients with progressive cirrhosis, leading to more difficulty with radiologic and pathologic diagnoses.8 SexA distinct female preponderance has been reported in surgical series, with a female-to-male ratio ranging from 5:1 to 6:1. However, in children and in autopsy series, cavernous hemangioma of the liver affects males and females equally . AgeHemangiomas can occur in individuals of any age. The tumors frequently occur in middle-aged women. Clinical DetailsThe vast majority of hemangiomas (as many as 85%) are asymptomatic; however, hemangiomas may cause symptoms because of the compression of adjacent structures, rupture, acute thrombosis, or consumptive coagulopathy (ie, Kasabach-Merritt syndrome). Preferred ExaminationMost patients with liver hemangioma are asymptomatic. Clinical findings usually do not contribute to the diagnosis. Laboratory test results may suggest anemia, and reduced hematocrit levels may be present in patients who have ruptured hemangiomas. In patients who have giant hemangiomas that are associated with Kasabach-Merritt syndrome, bleeding and clotting laboratory parameters may be abnormal. Most hemangiomas are incidentally detected on imaging studies. Ultrasonography is a cost-effective imaging modality for the diagnosis of a hemangioma. However, computed tomography (CT) scanning and/or MRI may be required to specifically diagnose a hemangioma. Limitations of TechniquesUltrasonography is a heavily operator-dependent technique; its performance depends on the expertise and experience of the ultrasonographer. In addition, the acquisition of satisfactory images in obese patients is technically difficult. Contrast-enhanced CT scanning is relatively contraindicated in patients who have renal insufficiency and in those who have a previous history of hypersensitivity to iodinated contrast agents; thus, MRI may be the preferred modality of choice in the characterization of hemangiomas in such patients. Angiography is an invasive method that is used for the characterization of liver hemangiomas; this imaging modality is associated with low but definite risks of morbidity and mortality. DIFFERENTIALSSection 3 of 11
Focal Nodular Hyperplasia Hepatocellular Carcinoma Liver, Metastases Other Problems to Be ConsideredHepatoma
CT SCANSection 4 of 11
FindingsHemangiomas are enhancing lesions that have characteristic dynamic features after the administration of contrast material. On nonenhanced CT scans, hemangiomas appear hypoattenuating relative to the adjacent liver. Calcification is uncommon; it may be marginal or central, spotty or chunky.12 During the arterial-dominant phase, small hemangiomas show intense and uniform contrast enhancement and retain their contrast enhancement during the portal venous phase (see Image 1).4 Wedge-shaped subcapsular or segmental perilesional enhancement may be noted adjacent to high-flow hemangiomas. These findings are possibly due to hemodynamic alterations in the liver.13 The pattern of a peripheral, discontinuous, intense nodular enhancement during the arterial-dominant phase with progressive centripetal fill-in on CT scans is considered pathognomonic for hemangiomas (see Image 2). Pathologically, the nodular areas consist of small vascular spaces that are more densely packed than the rest of the lesion. Atypical features of hemangiomas include the presence of arterioportal shunts and capsular retraction.5, 14 Rarely, a centrifugal pattern of contrast enhancement is seen.15 Degree of ConfidenceA globular enhancement pattern on CT scans (analogous to contrast-agent puddling on angiograms) is considered a highly sensitive (88%) and specific (84-100%) feature of hemangiomas.16, 17 Hemangiomas that show early, homogeneous contrast enhancement on dynamic CT scans and/or MRI may be mistaken for other hypervascular liver tumors such as hepatoma, focal nodular hyperplasia, adenoma, and hypervascular metastases. The absence of a history of cirrhosis and/or primary malignancy is an important factor in diagnosing hemangioma. The characteristic features of a hemangioma on dynamic CT scanning, red blood cell scintigraphy, and/or MRI permit confident diagnosis in more than 95% of cases. MRISection 5 of 11
FindingsMRI is more sensitive and specific than other imaging modalities in the diagnosis of hemangiomas. Hemangiomas appear as smooth, lobulated, homogeneous, sometimes septated, hypointense lesions on T1-weighted images. On T2-weighted images, they appear hyperintense relative to the liver (ie, more pronounced on fast spin-echo images), and they remain as bright as cerebrospinal fluid or bile with increased echo time (TE) (see Image 3).18 The high signal intensity on T2-weighted images is due to the extremely long T2 relaxation time of the free fluid (ie, slowly moving blood). The T2 relaxation time is directly proportional to the collective size of the hemangioma's constituent vascular spaces.19 The T2 values for hemangiomas vary between 90 and 200 msec, compared with T2 values >300 msec for cysts. Rarely, the imaging features of heavily fibrotic (hyalinized) hemangiomas can be mistaken for those of metastases.20 With the injection of contrast material (gadolinium chelates), lesions typically demonstrate peripheral nodular enhancement with progressive, centripetal fill-in that usually appears after 5-30 minutes (see Image 4). Large hemangiomas may appear cystic on images as a result of recurrent hemorrhage or myxomatous degeneration. In some hemangiomas, MRI may demonstrate fluid-fluid levels due to the sedimentation of blood products. The supernatant layer consists of unclotted serous blood, and the sediment consists of red blood cells. Definitive diagnosis is often difficult.21 Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. As of late December 2006, the FDA had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness withtrouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape. Degree of ConfidenceMRI is more sensitive and specific than other imaging modalities in the diagnosis of hemangiomas. On the basis of liver hemangioma characteristics on T2-weighted images (both morphologic and quantitative T2 values), MRI has a sensitivity of 100%, a specificity of 92%, and an accuracy rate of 97%. Hemangiomas that show early, homogeneous contrast enhancement on dynamic CT scans and/or MRI may be mistaken for other hypervascular liver tumors such as hepatoma, focal nodular hyperplasia, adenoma, and hypervascular metastases. The absence of a history of cirrhosis and/or primary malignancy is an important factor in diagnosing hemangioma. The characteristic features of a hemangioma on dynamic CT scans, red blood cell scintigraphy, and/or MRI permit confident diagnosis in more than 95% of cases. ULTRASOUNDSection 6 of 11
FindingsAt ultrasonography, hemangiomas appear as well-circumscribed, uniformly hyperechoic lesions (see Image 5). The increased echogenicity has been postulated to be caused by multiple interfaces between the walls of the cavernous spaces and the blood within them.22 In a study by Taboury et al, more than 75% of hemangiomas had posterior acoustic enhancement that the authors believed was correlated with hypervascularity at angiography.23 In large hemangiomas, heterogeneous areas are interspersed within the hyperechoic mass. Atypical features include hypoechoic lesions with a thin hyperechoic rim or a thick rind and scalloped borders.4 Note that hemangiomas may appear hypoechoic in fatty livers.24 Color power or duplex Doppler ultrasound examinations have a limited role in the specific diagnosis of hemangioma.25 Occasionally, a kilohertz shift in the low to mid range may be observed in the peripheral and central blood vessels in the hemangiomas. NUCLEAR MEDICINESection 7 of 11
FindingsRed blood cell-tagged technetium-99m (99mTc) scintigraphy with single photon emission CT (SPECT) scanning permits a specific diagnosis of hemangiomas.26 The lesions characteristically show decreased activity on early dynamic images and delayed filling from the periphery of the lesion. Degree of ConfidenceThe reported sensitivity is 97%, specificity 83%, and accuracy 96% for red blood cell-tagged 99mTc scintigraphy in the diagnosis of hemangiomas. Hemangiomas that show early, homogeneous contrast enhancement during dynamic CT scanning and/or MRI may be mistaken for other hypervascular liver tumors such as hepatoma, focal nodular hyperplasia, adenoma, and hypervascular metastases. The absence of a history of cirrhosis and/or primary malignancy is an important factor in diagnosing hemangioma. The characteristic features of a hemangioma on dynamic CT scans, red blood cell scintigraphy, and/or MRI permit confident diagnosis in more than 95% of cases. ANGIOGRAPHYSection 8 of 11
FindingsAt angiography, the feeding vessels of the hemangioma are of normal caliber, except those in the large tumors. During the late arterial/hepatic parenchymal phases, a dense, nodular pattern of opacification of the dilated vascular spaces persists into the venous phase.27 Degree of ConfidenceAlthough hemangiomas have characteristic angiographic features, the use of angiography is not warranted in the diagnosis of hemangioma, given the diagnostic capabilities of less invasive techniques, such as helical CT scanning and MRI. INTERVENTIONSection 9 of 11
Most hemangiomas are asymptomatic and treated conservatively with watchful expectancy. Absolute indications for surgery include rupture, a rapid change in size, and the presence of Kasabach-Merritt syndrome.28, 29 Large symptomatic hemangiomas are a relative indication for surgery. Surgical enucleation with blunt dissection is the preferred surgical technique; the surgical mortality and morbidity rates are negligible when an experienced surgeon performs the procedure. In symptomatic patients who are poor surgical candidates, transcatheter embolization is an attractive alternative.6, 27 MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Cavernous Hemangioma, Liver excerpt Article Last Updated: Aug 29, 2007 | ||||||||||||||||||||||||||||||||||||||||||
