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Benign Focal Lesions


Etiology

Although benign hepatic tumors have been classified into several histiotypes according to their cell of origin (i.e., hepatocytes, biliary epithelium, or mesenchymal cells), our focus in this discussion is on those lesions most frequently encountered in clinical practice, including simple (nonparasitic) cyst, hemangioma, hepatocellular adenoma, focal nodular hyperplasia (FNH), large benign regenerative nodules, and hepatic abscess ( Table 36-1 ).

TABLE 36-1
Clinical and Radiologic Features of Benign Hepatic Neoplasms
Neoplasm Sex Age Capsule Size Number Calcifications Fat Scar Bleed Associated Signs and Predisposing Factors
Hepatic cyst F > M 5th-6th decade No Variable One or few Rare (peripheral) No No Rare Congenital
Cavernous hemangioma F > M 2nd-5th decade No Variable (3-20 cm) One or few Sometimes in large ones No Rare (larger lesions) No Congenital
Capillary hemangioma F > M 2nd-5th decade No Usually smaller than 2 cm One or few No No No No Congenital
Focal nodular hyperplasia F ≫ M 3rd-4th decade No 3 cm (1-14 cm) One or few 1% Very rare Present in 50%
Hyperintense on T2-weighted images and on delayed post–gadolinium T1-weighted images		 No Vascular abnormality
Hepatocellular adenoma F ≫ M 3rd-4th decade 25% 5.5 cm One or few 5% Often No Yes Oral contraceptives assumption
Large benign regenerative nodules F > M 3rd-4th decade No 0.5-4 cm Multiple No No Larger lesions No Budd-Chiari syndrome and other vascular disorders
Pyogenic abscess F = M 5th-7th decade Yes Variable One or few No No No No Bacterial
F, Female; M, male.

Prevalence and Epidemiology

With the widespread use of sensitive imaging studies, benign hepatic tumors are increasingly reported. Notably, even in patients with a known primary malignancy, approximately 50% of small hepatic lesions (<1.5 cm) are benign.

Clinical Presentation

Most benign hepatic tumors are an incidental finding in asymptomatic patients during imaging workup for an unrelated medical problem. Larger lesions may occasionally produce signs and symptoms related to mass effect, such as abdominal discomfort and pain.

Hepatocellular adenoma (HCA) can manifest as acute onset of abdominal pain after intratumoral hemorrhage, whereas hepatic abscess is often accompanied by fever and leukocytosis.

Pathophysiology

Although benign tumors can occur in every portion of the liver, the right and left hepatic lobes are unequally affected by some histiotypes.

Pathology

Pathologic findings vary greatly according to the specific tumor type, and their appearance will be described in the sections on specific lesions.

Imaging

Although combining multiple imaging studies allows a confident diagnosis in the majority of cases, atypical lesions may still represent a diagnostic challenge.

Computed Tomography

With the advent of multidetector computed tomography (MDCT), remarkable improvements have been accomplished with scanning speed, scan volumes, and image quality. As a result, CT currently represents the most commonly used imaging modality for evaluating the liver.

Besides lesion detection, the main goal of CT is to firmly establish a diagnosis of benign hepatic tumors. Indeed, mistaking an incidental benign lesion for a malignant tumor may lead to unnecessary aggressive management or possibly preclude surgery when benign and malignant lesions coexist within the same liver. Although simple cysts can be confidently characterized based only on their appearance on precontrast and single-phase contrast-enhanced CT during the portal venous phase, reliable diagnosis of other benign hepatic tumors generally requires assessment of lesion enhancement pattern with multiphasic contrast-enhanced CT (i.e., hepatic arterial phase, portal venous phase, and delayed phase).

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) represents a powerful technique for the detection and characterization of either benign or malignant liver tumors. MRI protocol includes pulse sequences that assess different tissue characteristics such as T1 and T2 contrast of liver tumors, as well as assessment of tumor-specific enhancement patterns after intravenous administration of gadolinium-based contrast agents. Diffusion weighted imaging measures the microscopic movement of water molecules, which is related to tissue cellularity and organization. Hepatobiliary contrast materials (gadobenate dimeglumine [Gd-BOPTA] and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid [Gd-EOB-DTPA]) distribute in the extracellular fluid compartment first and subsequently enter functioning hepatocytes. This provides additional information, especially to differentiate lesions with functioning hepatocytes (i.e., lesions with organic anionic transport proteins) from hepatocellular lesions without organic anionic transport proteins and nonhepatocellular lesions.

Ultrasonography

Because of its high contrast resolution, low cost, and wide availability, ultrasonography frequently represents the primary modality for the study of the liver. However, operator dependency, substantial image degradation in obese patients, and a limited field of view, represent major limitations that explain the low appeal of ultrasonography among referring physicians and surgeons.

Some benign liver tumors, such as simple cysts or hemangiomas, typically demonstrate a classic, virtually diagnostic appearance on ultrasonography. Some other lesions (e.g., FNH) may, however, be difficult to distinguish from normal liver owing to their hepatocellular nature.

Microbubble contrast agents have substantially enhanced the available diagnostic information. Besides the evaluation of tumor enhancement pattern during both arterial and portal venous phases, contrast-enhanced images also can be acquired during a late parenchymal phase with potential improvement of lesion detection.

Specific Lesions

Simple (Bile Duct) Cyst

Etiology

Simple (nonparasitic) cysts likely result from a congenital defective development of the intrahepatic biliary ducts.

Prevalence and Epidemiology

Simple hepatic cysts are among the most common liver lesions, with an estimated incidence of 2.5% in the general population. Although cysts can occur in both sexes at all ages, middle-aged women are more frequently affected (male-to-female ratio, 1:5).

Clinical Presentation

Typically, cysts are incidental imaging findings in asymptomatic patients. Occasionally, larger lesions may produce signs and symptoms related to mass effect, such as abdominal discomfort, chronic pain, nausea and vomiting, or early satiety because of compression of the stomach. Rarely, acute pain can develop after intralesional hemorrhage, spontaneous or traumatic rupture, or secondary infection.

Pathophysiology

Simple cysts originate twice as frequently within the right lobe of the liver than the left lobe.

Pathology

Typically, simple cysts manifest as either solitary or multiple, well-defined lesions, varying in size from a few millimeters to several centimeters. Cysts do not communicate with the biliary tree and typically contain clear fluid. Occasionally, however, cystic content may be mucoid, purulent (if the cyst is infected), or hemorrhagic.

On histologic examination the cyst lining consists of a single layer of columnar or cuboid epithelium, which is identical to bile duct epithelium. Epithelial cells rest on a basement membrane surrounded by a thin fibrous stroma.

Liver Function

Liver function test results are generally unremarkable, although larger cysts may produce mild increase of alkaline phosphatase and bilirubin levels if there is mild mass effect on the intrahepatic biliary ducts.

Imaging

Because of the high incidence in the general population, simple hepatic cysts are frequently discovered on ultrasonography, CT, or MRI of the liver.

Computed Tomography.

On precontrast CT, cysts manifest as rounded or oval, thin-walled, well-defined, water-attenuating (from −10 to +20 Hounsfield units) lesions. Although most cysts are unilocular in appearance, multiple lesions that are clustered together may produce the appearance of a single, multiloculated lesion.

On contrast-enhanced CT, neither the cyst content nor the peripheral wall shows perceptible enhancement ( Figure 36-1 ). Rarely, complicated cysts may show atypical appearances, such as parietal calcifications, mural nodularity, or fluid levels that may resemble a cystic liver tumor or hepatic abscess.

Figure 36-1, Typical presentation of hepatic (bile duct) simple cyst. A, Transverse precontrast computed tomography (CT) image shows a large, sharply defined lesion (arrow) in the left lobe of the liver that is hypoattenuating compared with the surrounding hepatic parenchyma and aorta. Hypoattenuation to the aorta on precontrast images is the single most important finding to diagnose cystic lesions on CT. B, Corresponding contrast-enhanced CT scan during portal venous phase demonstrates absence of lesion enhancement. C, Ultrasound image in a different patient shows a round, well-circumscribed mass (arrow) with imperceptible wall and increased through-transmission of sound waves.

Magnetic Resonance Imaging.

Because cysts are composed almost entirely of fluid, their T1 and T2 values are extremely long, thus explaining the very low signal intensity on T1-weighted images and markedly high signal intensity on T2-weighted images ( Figure 36-2 ). Characteristically, cysts further increase their relative signal on T2-weighted images at longer echo times because of signal suppression from most abdominal parenchymal tissues. Hemorrhagic cysts can show variable signal intensity on T1- and T2-weighted images according to the age of hemorrhage and a fluid/fluid level as a result of mixed blood product. On diffusion weighted images, cysts typically show signal intensity decrease with increasing b-values, and strong hyperintensity on apparent diffusion coefficient (ADC) map.

Figure 36-2, Typical presentation of hepatic (bile duct) simple cyst. A, Fat-suppressed T2-weighted fast spin echo magnetic resonance (MR) image shows markedly high intensity of the cyst (arrow). B, Gadolinium-enhanced T1-weighted gradient recalled echo MR image during portal venous phase demonstrates absence of lesion enhancement. C to E, On diffusion weighted images at b = 0 sec/mm 2 (C), b = 150 sec/mm 2 (D), and b = 800 sec/mm 2 (E) the cyst shows intensity decrease with increasing b-value. F, On corresponding apparent diffusion coefficient map the cyst shows strong hyperintensity.

As in the case of contrast-enhanced CT, simple cysts do not enhance on gadolinium-enhanced MRI. On hepatobiliary phase, cysts remain hypointense relative to the liver and biliary system. The lack of communication between cysts and the biliary tree can be demonstrated on T1-weighted magnetic resonance cholangiopancreatography (MRCP) after administration of hepatobiliary contrast agents, which demonstrate markedly increased signal intensity of the biliary tree and gallbladder but not of the noncommunicating liver cyst.

Ultrasonography.

Typically, hepatic cysts manifest as well-defined, anechoic lesions with well-defined margins and posterior acoustic enhancement on gray-scale ultrasonography (see Figure 36-1 ). Complicated cysts may show atypical appearances, such as internal septations, debris, and a thickened wall with or without calcification.

Imaging Algorithm.

An ideal algorithm is presented in Figure 36-15 , at the end of this discussion.

Classic Signs
Simple Cysts

  • Thin wall

  • Anechoic cystic content and posterior echo enhancement

  • No contrast enhancement after intravenous injection of a contrast agent

  • Fluid filled

  • Homogeneous

Differential Diagnosis

Clinical findings usually do not contribute to the diagnosis of simple hepatic cysts. Strong hyperintensity on heavily T2-weighted MR images allows differentiation from most hepatic metastases, with the exception of those originating from neuroendocrine tumors. Unlike hepatic abscesses or cystic neoplasms, hepatic cysts manifest with a very thin, almost imperceptible nonenhancing wall, as well as lack of intralesional septa and mural nodules. Polycystic liver disease usually consists of numerous cystic lesions, with size varying from a few millimeters to several centimeters, and is associated with autosomal dominant polycystic kidney disease. Hydatid cyst usually contains several daughter cysts and is surrounded by calcified walls. Biliary hamartomas are usually numerous and smaller than 15-mm cystic lesions, whereas Caroli's disease will consist of multisegmental biliary dilatation, typically showing the “central dot sign,” owing to a portal venous branch surrounded by a cystic lesion secondary to arrested development of the intrahepatic biliary tree ( Figure 36-3 and Table 36-2 ).

Figure 36-3, Imaging findings and differential diagnosis among different cystic lesions of the liver, including hydatid cyst, simple cyst, pyogenic abscess, biliary cystadenoma, polycystic liver disease, biliary hamartomas, and Caroli's disease. A to F, Portal venous phase computed tomography. G, Gadolinium-enhanced T1-weighted gradient recalled echo magnetic resonance image. A, Calcified wall (black arrow), thick enhancing wall (arrow), and daughter cysts (asterisks) are typical of hydatid cyst. B, A simple hepatic cyst has no visible wall (arrow). Note the mild intrahepatic biliary dilatation (arrowhead) secondary to mass effect in both cases. Other findings that may help in narrowing differential diagnosis when facing cystic liver lesions are ( C and D ) thick enhancing walls ( arrow, C ) and internal septa ( arrow, D ) in pyogenic liver abscess and biliary cystadenoma, (E) multiplicity and partially calcified walls in polycystic liver disease, (F) small size (<15 mm) and multiplicity (arrows) in biliary hamartomas, and (G) demonstration of a “dot sign” (arrow) resulting from a centrolesional portal venous branch in Caroli's disease.

TABLE 36-2
Demographics and Pathologic and Clinical Features of Hydatid Cyst, Simple Cyst, Pyogenic Abscess, Biliary Cystadenoma, Polycystic Liver Disease, Biliary Hamartomas, and Caroli's Disease
Features Hydatid Cyst Simple Cyst Pyogenic Abscess Biliary Cystadenoma Polycystic Liver Disease Biliary Hamartomas Caroli's Disease
Sex F = M F > M F = M F > M F > M M > F F > M
Age 3rd-4th decade 5th-6th decade 5th-7th decade 2nd-5th decade 5th-6th decade Any age 2nd-3rd decade
Frequency Depend on geographic area Very common Common Rare Rare Common Very rare
Clinical Features Asymptomatic Asymptomatic Fever, pain Asymptomatic Mass effect Asymptomatic Fever (cholangitis)
Location Right lobe > left All liver segments Right lobe > left Right lobe > left All liver segments All liver segments All liver segments
Number Multiple (60%) Solitary > Multiple Multiple Solitary Multiple Multiple Multiple
Size 3-30 cm 0.5-30 cm 0.5-10 cm 1-20 cm 1-10 cm <15 mm 0.5-5 cm
Wall calcification Yes Rare, peripheral No Rare Rare No No
Septations Present Absent Present Present Absent Absent Absent
Gas No No Present (20%) No No No No
Inflammatory changes Absent Absent Present Absent No No No
Multiplicity Possible Absent Present No No No Yes
Signs at imaging and associated conditions Intralesional daughter cysts and wall calcifications Increased through-transmission on ultrasonography, hypoattenuation to blood pool on unenhanced CT Cluster sign Adult recessive polycystic kidney disease Multiplicity and small (<15 mm) size, congenital hepatic fibrosis, Caroli's disease Dot sign, congenital hepatic fibrosis, biliary hamartomas
CT, Computed tomography; F, female; M, male.

Treatment

Medical Treatment.

Because simple cysts are rarely complicated, they should be treated conservatively.

Surgical Treatment.

Percutaneous catheter drainage with alcohol sclerosis can be an effective therapy for larger, symptomatic cysts. Rarely, hepatic cysts are treated surgically, most commonly via laparoscopic fenestration.

What the Referring Physician Needs to Know
Simple Cysts

  • Simple cysts are among the most common liver lesions.

  • Conservative management is warranted with the exception of larger, symptomatic cysts.

  • Ultrasonography is usually sufficient to confirm or rule out the diagnosis.

Hepatic Hemangioma

Etiology

Hemangiomas are probably congenital in origin, and no definite predisposing factors have been identified. Because they increase with multiparity, female sex hormones have been suggested as a cause.

Prevalence and Epidemiology

Hemangioma is the most common benign hepatic tumor, with an estimated incidence of 5% to 20% in the general population. Although hemangiomas can occur in both sexes at all ages, middle-aged women are more frequently affected, perhaps reflecting the causative effect of female sex hormones.

Clinical Presentation

Typically, hemangiomas are incidental imaging findings in asymptomatic patients. Occasionally, larger lesions may produce signs and symptoms related to mass effect, such as upper abdominal mass, abdominal discomfort, and pain. Rarely, sudden onset with acute pain can develop after either spontaneous or traumatic rupture of larger lesions. Giant hemangiomas can manifest as thrombocytopenia and consumptive coagulopathy (Kasabach-Merritt syndrome).

Pathophysiology

Hemangiomas can occur in all liver segments with equal frequency.

Pathology

Characteristically, hemangiomas manifest as either solitary or multiple, well-defined masses, varying in size from a few millimeters to several centimeters. Hemangiomas are infrequently detected or are generally smaller when occurring within a cirrhotic liver, probably owing to progressive tumor shrinkage by liver fibrosis. On sectioning, hemangiomas show a typical red-blue appearance with a spongy or honeycombing surface. Organized thrombi, fibrosis, and calcification may be noted grossly, particularly in the central area of larger lesions. Occasionally, sclerosis may involve the entire lesion, which manifests as a firm, gray-white nodule of fibrous tissue (the so-called sclerosed hemangioma ).

Association of hemangioma with other benign liver lesions, such as FNH and hepatocellular adenoma, has been described.

On histologic examination, hemangioma consists of several communicating blood-filled spaces, lined by a single layer of flat endothelial cells, which are supported by a thin basement membrane.

Liver Function

Liver function test results are generally unremarkable, although patients with giant hemangiomas occasionally can have a mild increase in alkaline phosphatase level.

Imaging

Because of the high incidence in the general population, hemangiomas are frequently discovered incidentally on ultrasonography, CT, or MRI of the liver.

Computed Tomography.

On precontrast CT, most hemangiomas manifest as hypoattenuating lesions relative to the liver. However, because lesions may be hyperattenuating if occurring in the setting of diffuse fatty liver disease secondary to uniformly decreased attenuation of the hepatic parenchyma, a more reliable criterion for the diagnosis of hemangioma is isoattenuation to the aorta and intrahepatic vessels. Central calcifications may occur in giant hemangiomas.

With contrast-enhanced CT, hemangiomas classically show early, discontinuous, peripheral, nodular enhancement, with centripetal progression. The enhancing areas of hemangiomas are isoattenuating to the aorta during the hepatic arterial phase and to blood pool during the portal venous phase and delayed phase ( Figure 36-4 ). When all typical criteria are observed, lack of complete lesion enhancement on the delayed phase should not dissuade from the diagnosis of hemangioma. Giant hemangiomas usually lack complete enhancement on delayed phase imaging owing to thrombosis or sclerosis of the central portion of the tumor.

Figure 36-4, Typical cavernous hemangioma. A, Transverse precontrast computed tomographic image shows a 4-cm, hypoattenuating lesion (arrow) in the right lobe of the liver. Note the equal attenuation of the lesion with both aorta (A) and intrahepatic vessels. B and C, Coronally reformatted images of the same patient demonstrate nodular, peripheral, discontinuous enhancement ( arrowhead, B ) on both (B) hepatic arterial phase and (C) portal venous phase, which is comparable to vessels on all vascular phases. D, Ultrasound image in a different patient shows a homogeneous, well-defined, hyperechoic lesion (arrow) of the right hepatic lobe.

Small hemangiomas (<2 cm)—also known as capillary hemangiomas or flash filling hemangiomas —may enhance rapidly and homogeneously during the hepatic arterial phase ( Figure 36-5 ), thus mimicking other benign or malignant hypervascular liver tumors ( Tables 36-3 and 36-4 ). Transient peritumoral enhancement during the hepatic arterial phase is frequently observed owing to associated arteriovenous shunt.

Figure 36-5, Imaging findings and differential diagnosis between capillary hemangioma and hypervascular metastases from breast carcinoma on transverse contrast-enhanced computed tomography during hepatic arterial phase. A, Capillary hemangioma (arrow) manifests as an isoattenuating lesion compared with the aorta, surrounded by a wedge-shaped, homogeneous, moderately hyperattenuating area (arrowheads) secondary to arteriovenous shunt. B, Hypervascular metastases (arrows) are multiple and demonstrate more heterogeneous enhancement, which is not as strong as that of the aorta (A). Enhancement characteristics along with a history of primary tumor allow the correct diagnosis.

TABLE 36-3
Differential Features Among Capillary Hemangioma, Cavernous Hemangioma, Metastases, Focal Nodular Hyperplasia, and Large Benign Regenerative Nodules
Features Capillary Hemangioma Cavernous Hemangioma Metastases Focal Nodular Hyperplasia Large Benign Regenerative Nodules
Sex F > M F > M M = F F ≫ M F > M
Age 2nd-5th decade 2nd-5th decade 6th-7th decade 3rd-4th decade 3rd-4th decade
Ultrasound findings Hypointense with hyperechoic border Hyperechoic Hypoechoic Isoechoic Variable
Sustained enhancement on portal venous and delayed phases Yes Yes No Yes Yes
Isoattenuating to vessels on CT Yes Yes No No No
Hyperintensity on T2 Strong Strong Mild * Mild No
Homogeneous enhancement on hepatic arterial phase Yes No No Yes Yes
Enhancement Homogeneous Peripheral, discontinuous Peripheral, ringlike Homogeneous Homogeneous
Calcifications No Central if present No † 1% No
Scar No Rare (larger lesions) No Yes Larger lesions
Necrosis No No Yes No No
Number Single > multiple Single > multiple Multiple Single (75%) Multiple
History of malignancy No No Yes No No
CT, Computed tomography; F, female; M, male.

* Except for neuroendocrine tumors, mucinous colon cancer, and breast cancer that may be strongly hyperintense.

† Except for mucinous colon cancer metastases that may have scattered calcifications.

TABLE 36-4
Differential Features Among Focal Nodular Hyperplasia, Large Benign Regenerative Nodules, Hepatocellular Adenoma, Hepatocellular Carcinoma, Hypervascular Metastases, and Cavernous Hemangioma
Features FNH LBRN HCA/Adenomatosis HCC Hypervascular Metastases Cavernous Hemangioma
Sex F ≫ M F > M F ≫ M M > F M = F F > M
Age 3rd-4th decade 3rd-4th decade 3rd-4th decade 6th-7th decade 6th-7th decade 2nd-5th decade
History of cirrhosis No No No Yes No No
Association with use of oral contraceptives No No Yes No No No
Liver morphology Normal Normal Normal Abnormal Normal Normal
Ultrasound findings Isoechoic Variable Variable Hypoechoic Hypoechoic Hyperechoic
Hypervascularity on hepatic arterial phase Strong Strong Mild to strong * Mild Mild Nodular, peripheral
Homogeneity Yes Yes No No No No
Calcifications 1% No Rare Rare No Rare (larger lesions)
Signal drop on out-of-phase MRI Rare No Yes Rare No No
Signal intensity on T2 Hyperintense (mild) Hypointense Hyperintense (mild to strong * ) Hyperintense (mild) Hyperintense (mild † ) Hyperintense (strong)
Washout on portal venous and delayed phases No No Yes Yes Yes No
Signal intensity on hepatobiliary phase Isointensity or hyperintense Isointensity or hyperintense Hypointense Hypointense Hypointense Hypointense
F, Female; FNH, focal nodular hyperplasia; HCA, hepatocellular adenoma; HCC, hepatocellular carcinoma; LBRN, Large benign regenerative nodules; M, male; MRI, magnetic resonance imaging.

* Findings depending on HCA subtype.

† Except for neuroendocrine tumors, mucinous colon cancer, and breast cancer that may be strongly hyperintense.

A sclerosed hemangioma usually lacks any contrast enhancement on different vascular phases.

Magnetic Resonance Imaging.

Because hemangiomas are composed almost entirely of blood, their T1 and T2 values are very long, thus explaining the very low signal intensity on T1-weighted images and markedly high signal intensity on T2-weighted images, even at longer echo times. The complex internal architecture of giant hemangiomas can be better depicted on T2-weighted images as low-signal strands of fibrous stroma, which gives the lesion a characteristic appearance. On diffusion weighted images, hemangiomas typically show marked hyperintensity at b 0 s/mm 2 , with signal intensity decrease or persistent hyperintensity (T2 shine-through effect) at high b-values, and moderate hyperintensity on ADC map. The ADC values of hemangiomas are lower than those of simple cysts. On dynamic phases, hemangiomas show an enhancement pattern, which is substantially comparable to that with CT ( Figure 36-6 ). In the hepatobiliary phase, hemangiomas retain the contrast material, but they typically show hypointensity because of increased signal intensity of the surrounding liver. With Gd-EOB-DTPA, however, hemangiomas can show isointensity or hypointensity on portal venous and 3-minute delayed phases (pseudo washout) or they can show peripheral hypointensity in the hepatobiliary phase.

Figure 36-6, Imaging findings and differential diagnosis on magnetic resonance imaging (MRI) between cavernous hemangioma and hypervascular sarcoma metastasis coexisting in the same liver. A, Although both lesions are hypointense to surrounding liver parenchyma on T1-weighted gradient recalled echo MRI, metastasis ( horizontal arrow, B ) shows moderate hypervascularity and rapid washout on gadolinium-enhanced T1-weighted gradient recalled echo MR image during the hepatic arterial phase (B) and portal venous phase (C), respectively. B and C, In the same imaging phases, cavernous hemangioma ( vertical arrow, B ) typically shows nodular, peripheral, discontinuous enhancement, which progresses centripetally. D, Fat-suppressed T2-weighted fast spin echo MR image shows strong hyperintensity of hemangioma with only moderate hyperintensity of metastasis.

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