Hemangioma is the most common benign tumor of the liver. Unlike cavernous hemangioma, hepatic capillary or mixed capillary-cavernous hemangioma is a rare type of tumor in adults. Clinical presentation of hemangioma may mimic that of hepatocellular carcinoma. Furthermore, radiologic features on computed tomography and magnetic resonance imaging may not be typical for hemangioma and can be confused with hepatocellular carcinoma. Symptomatic hemangiomas require some form of treatment, such as corticosteroids, interferon, radiation, arterial embolization, surgical resection, or liver transplant. In the present case study, we present a patient treated with liver transplant for hemangioma mimicking hepatocellular carcinoma. This case report illustrates the atypical imaging appearance of hemangioma and possible confusion it can cause in diagnosing hepatocellular carcinoma, especially in a hepatitis C carrier.

Key words : Hemangioma, Capillary-cavernous type, Hepatocellular carcinoma, Liver transplant

Introduction

The most common benign tumor of the liver is cavernous hemangioma with reported incidences of 0.4% to 7.3%.¹ Small capillary hemangiomas are of no clinical significance, whereas the larger cavernous hemangiomas more often come to the attention of the liver surgeon. Women are predominantly affected and often present at a younger age with larger tumors than do men.² Most hepatic hemangiomas are asymptomatic; however, those with a diameter > 4 cm are termed giant hematomas, and they are usually manifested by nonspecific abdominal pain, dyspeptic syndrome, and rarely by hemorrhage, or jaundice. Thrombocytopenia and consumptive coagulopathy are rare but well described.³ Despite the benignity of the lesion, hemangioma-related arterioportal shunt also has been reported.⁴

From the pathological view, they may be classified as small (capillary) or large, with cavernous vascular spaces that may show scarring, thrombosis, calcifications, and hyalinization.⁵ The polymorphic imaging appearance of hemangiomas depends on their histologic features and flow pattern. The widespread use of cross-sectional imaging has allowed an increased detection rate and a better characterization of this benign tumor. Recent developments in computed tomography and magnetic resonance imaging providing high spatial and temporal resolution, together with the use of new contrast agents and/or pulse sequences, which has broadened the spectrum of imaging findings, contributing to diagnostic refinement in difficult cases.⁶ However, rare variants like sclerosing hemangioma and capillary, or mixed capillary-cavernous types, may be difficult to diagnose and can easily be confused with hepatocellular carcinoma.

Symptomatic giant hemangiomas require some form of treatment, such as corticosteroids, interferon, radiation, arterial embolization, or surgical resection. However, at the very end of the spectrum, liver transplants have been done for massive hemangiomas or giant hemangiomas causing severe coagulopathy.^{3, 7}

We present a patient treated with a liver transplant for hemangioma mimicking hepatocellular carcinoma. This case report serves to illustrate the atypical imaging appearance of hemangioma and the possible confusion it can cause in diagnosing hepatocellular carcinoma, especially in a hepatitis C carrier.

Case Report

A 56-year-old woman presented with right, upper-quadrant pain. Her hepatitis C had been diagnosed 3 years earlier at an outside hospital. She never had ascites, jaundice, encephalopathy, or bleeding. Her past medical history was unremarkable except for 10 years’ hypertension. Her family history revealed diabetes in her father. She had a history of smoking and intravenous (IV) substance abuse. The patient was on amlodipine besylate and methadone, and never had been treated with interferon. On physical examination, there was tenderness in the right, upper quadrant. There were no other findings in the abdominal examination, and there was no edema in the extremities. The results of a complete blood count were normal except for moderate thrombocytopenia. Total bilirubin level was 3.4 µmol/L, partial thromboplastin time and international normalized ratio values were seen to be prolonged (42.5 seconds and 1.82). Creatinine was 194.48 µmol/L (2.2 mg/dL). Alanine transaminase and aspartate transaminase levels were also high (271 IU/L and 410 IU/L). Alkaline phosphatase level was normal. Alpha fetoprotein and CEA values also were within normal limits. Model for end-stage liver disease (MELD) score was calculated as 25. Albumin value was low 21 g/L (2.1 g/dL). Results of a chest radiograph and computed tomography were normal.

Computed tomography of the abdomen was obtained with oral and nonionic IV contrast administration. The liver was studied before, during, and immediately after a bolus of nonionic IV contrast medium. The computed tomography scan showed marked changes of cirrhosis in the liver. There was a 1.4-cm arterially enhancing mass in the left lobe, compatible with a focus of hepatoma (Figure 1). Portal hypertension was significant and manifested by gastric varices, multiple splenic collaterals, and significant splenomegaly. A 1-cm left para-aortic lymphadenopathy was seen. There was no dilatation in the biliary tree, but multiple stones were present in the gallbladder.

Magnetic resonance imaging was obtained through the abdomen with an axial T1-weighted breath-hold gradient echo in and opposed phase, and axial fat-suppressed T2-weighted images. Two-dimensional time-of-flight images were obtained through the portal vein. Three-dimensional volumetric fat-suppressed T1-weighted breath-hold gradient echo images were taken through the abdomen before and 3 times after the IV administration of gadolinium chelate. A 3-dimensional image after processing was performed. Twenty cc gadopentetate dimeglumine was used as contrast material. The liver demonstrated morphologic findings of cirrhosis with atrophy and nodularity of the parenchyma and contour. Portal hypertension was evident. There were no ascites. There was a T2 bright lesion in segment 3, 1.9 × 1.8 cm in diameter (Figures 2A and B). Minimal intrahepatic biliary distension and choledocholithiasis were seen. Hepatopetal flow was noted in the main portal vein. Mild periportal adenopathy was seen to be reactive. As a result, the unchanged 1.9 cm in diameter mass in the left lateral segment was consistent with hepatocellular carcinoma. Cirrhosis and portal hypertension also were noted.

Orthotopic liver transplant was performed for hepatocellular carcinoma. Grossly, the native liver was diffusely nodular. The hepatic cut surface was micronodular. In segment 3 of the liver, bordering segment 2, an oval-to-irregular, tan-red, hemorrhagic mass measuring 1.8 × 1.6 × 0.8 cm was identified (Figure 3). A second tan-to-brown oval nodule measuring 0.9 × 0.9 cm was seen in segment 6. There were more than 30 irregular black stones in the gallbladder. Histopathologic examination revealed hemangioma (predominantly capillary type) with minor cavernous components (mixed capillary-cavernous hemangiomas) (Figures 4, 5A, and 5B). End-stage liver disease with mild chronic hepatitis C, grade 2-stage 4 cirrhosis (modified grading by Ishak /staging system for chronic hepatitis) was present. The lesion in segment 6 showed a low-grade dysplasia. Gallbladder mucosa was atrophic with multiple stones.

The postoperative course was unremarkable. Subsequently, the results of all coagulation parameters returned to normal, and all laboratory tests were normal. The patient was discharged home on postoperative day 7. After 6 months, the patient remains well and is exercising all normal activities.

Discussion

Hemangioma is the most-common benign tumor of the liver, and its incidence ranges from 0.4% to 7.3% in autopsy series.¹ Most are asymptomatic, but giant hemangiomas, those with a diameter > 4 cm, can cause several symptoms. The most-common type of hepatic hemangioma is the cavernous hemangioma.^{1, 8} On occasion, this type of hemangiomas can undergo regressive changes with scarring, areas of thromboses, calcification, and extensive hyalinization.⁵ Rare variants like sclerosing hemangioma and capillary or mixed capillary-cavernous types may be difficult to diagnose, and can easily be confused with hepatocellular carcinoma.^9-11 The ability to accurately diagnose these lesions is crucial.

While liver hemangiomas can be accurately diagnosed with several radiologic studies, differentiation of cavernous hemangiomas (especially the rare variants) from malignant masses can be difficult. Ultrasonography, technetium-labeled red blood cell scintigraphy, dynamic contrast-enhanced computed tomography, and magnetic resonance imaging have been used as confirmatory investigations for the differential diagnosis. Recent developments in computed tomography and magnetic resonance imaging providing high spatial and temporal resolution, together with the use of new contrast agents and/or pulse sequences has broadened the spectrum of imaging findings, contributing to diagnostic refinement in difficult cases.⁶

Hepatocellular carcinoma is known to enhance in proportion to the degree of uptake of contrast medium, and because of its hypervascular nature, it enhances earlier than the surrounding hepatic parenchyma does.^{11, 12} After administration of contrast material as a bolus injection, dynamic computed tomography scanning results in improved delineation of tumor vascularity, venous shunting, venous occlusion, and segmental flow abnormalities. Hepatocellular carcinoma becomes maximally hyperdense during the arterial phases of dynamic scanning sequences, and then rapidly becomes less dense as portal flow to the liver becomes dominant. The pattern of a peripheral, discontinuous, intense nodular enhancement during the arterial-dominant phase of computed tomography with progressive centripetal fill-in is considered pathognomonic for hemangiomas.¹⁰ However, as seen in our case, hemangiomas can be more homogeneous in appearance during the dynamic phase of computed tomography. When diagnostic uncertainty exists after computed tomography or to confirm the diagnosis, magnetic resonance imaging is indicated.

The magnetic resonance imaging appearance of hemangiomas is of a smooth, lobulated, homogenous, sometimes septate, hypointense lesion on T1-weighted images.¹³ On T2-weighted images, they appear hyperintense relative to the liver. On magnetic resonance imaging, it is the high-signal intensity of cavernous hemangioma on heavily T2-weighted images that distinguishes them from malignancy; this is due to the long T2-relaxation time in the nonpulsatile, static blood in the endothelium-lined large vascular lakes and channels.^{6, 11} In our case, axial T1-weighted breath-hold gradient echo, in an opposed phase, and axial fat-suppressed T2-weighted images were obtained through the abdomen following the IV administration of gadolinium chelate. The unchanged 1.9-cm mass in segment 3 (bright appearance on T2) was consistent with hepatocellular carcinoma.

In this study, the presented patient was cirrhotic (HCV positive), and the radiologic diagnosis of hepatocellular carcinoma was misleading. In previous studies, magnetic resonance imaging had been shown to detect more lesions and overall smaller lesions compared with helical computed tomography, and may yield additional information on characterization of lesions.⁶ However, in Fung and associates systematic review of radiologic imaging for hepatocellular carcinoma in cirrhotic patients, no one imaging technique was superior.¹⁴ In our patient, the hepatic mass was small (almost 2 cm), and the imaging features were consistent with those of hepatocellular carcinoma. Therefore, a prior needle biopsy was not done, and the patient underwent liver transplant. The histopathologic evaluation revealed mixed capillary-cavernous pattern of hemangioma, which is known to rarely occur.

This case report serves to illustrate the imaging appearance of mixed capillary-cavernous hemangioma and the possible confusion it can cause in diagnosing hepatocellular carcinoma, especially in a hepatitis C carrier.

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