DOI: 10.1148/rg.242035079
RadioGraphics 2004;24:367-385
© RSNA, 2004
Hemangioma from Head to Toe: MR Imaging with Pathologic Correlation1
Joan C. Vilanova, MD,
Joaquim Barceló, MD,
James G. Smirniotopoulos, MD,
Ricard Pérez-Andrés, MD,
Miguel Villalón, MD,
Josefina Miró, MD,
Ferran Martin, MD,
Jaume Capellades, MD and
Pablo R. Ros, MD, MPH
1 From the Departments of Magnetic Resonance (J.C.V., J.B., M.V.) and Pathology (J.M., F.M.), Clínica Girona, Lorenzana 36, 17002 Girona, Spain; the Department of Radiology, Uniformed Services University, Bethesda, Md (J.G.S.); the Department of Radiology, Hospital Universitari "Germans Trias i Pujol," Badalona, Spain (R.P.A., J.C.); and the Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass (P.R.R.). Recipient of an Excellence in Design award for an education exhibit at the 2002 RSNA scientific assembly. Received March 24, 2003; revision requested May 14 and received June 19; accepted June 19. All authors have no financial relationships to disclose. Address correspondence to J.C.V. (e-mail: rmgirona@comg.es).
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Abstract
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Hemangioma is a common benign vascular neoplasm that closely resembles normal vessels and can be found in all organs of the human body. Vascular lesions can be classified as infantile hemangiomas or vascular malformations on the basis of their natural history, location, cellular turnover, and histologic characteristics. The magnetic resonance (MR) imaging features of vascular malformations of the central nervous system depend on the pathologic subtype. Soft-tissue vascular malformations can be categorized with combined MR imaging and MR angiography as either high- or low-flow. Osseous vascular malformations commonly demonstrate a high-signal-intensity trabecular pattern at both T1- and T2-weighted MR imaging. A group of more aggressive vascular neoplasms, including hemangioendothelioma, hemangiopericytoma, and glomus tumor, have a nonspecific appearance at MR imaging. In the liver and spleen, hemangiomas are typically hyperintense at T2-weighted MR imaging, with a centripetal filling pattern after administration of gadopentetate dimeglumine. Vascular lesions can involve several organs or systems in angiomatous syndromes. MR imaging allows characterization of a hemangioma with typical features, which vary depending on anatomic location. Familiarity with these features facilitates diagnosis and management of these anomalies.
© RSNA, 2004
Index Terms: Angioma, **.312 • Angioma, central nervous system, 10.3141, 30.3141 • Angioma, gastrointestinal tract, 761.31, 775.31 • Angioma, skeletal system, 40.3141 • Angioma, soft tissues, **.31 • Magnetic resonance (MR), vascular studies, **.12142
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LEARNING OBJECTIVES FOR TEST 1
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After reading this article and taking the test, the reader will be able to:
- Describe the typical MR imaging features of hemangioma in different organs or systems.
- Discuss the correlation between these MR imaging findings and pathologic features.
- Identify the MR imaging features of hemangioma and its variants that may allow a specific diagnosis.
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Introduction
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Vascular lesions are relatively common. However, the nomenclature for classifying these lesions is often complicated and confusing. Various classification systems have been used for vascular anomalies in both the central nervous system (1,2) and the soft tissues (3).
At pathologic analysis, vascular lesions can be classified as capillary, cavernous, venous, and arteriovenous malformations depending on the predominant anomalous vascular channels (1,4). Alternatively, malformations can be categorized as either high-flow (arteriovenous) or low-flow (capillary, cavernous, venous) vascular lesions (5). However, low-flow lesions can have mixed pathologic features and manifest with similar patterns at magnetic resonance (MR) imaging, making differentiation impossible (6).
MR imaging is useful for characterizing and determining the extent of vascular lesions. A combination of conventional MR imaging and dynamic contrast material–enhanced MR angiography is especially useful in distinguishing between high- and low-flow lesions (5,7).
The increased use of MR imaging as a whole-body diagnostic tool allows more frequent detection of hemangioma, either incidentally or as a clinical indication to characterize a tumor detected with other diagnostic techniques or to document the extent of the anomaly. MR imaging allows characterization of hemangiomas with typical features, which differ depending on anatomic location.
In this article, we discuss and illustrate the common MR imaging findings in vascular lesions of the brain, spine, liver, spleen, bone, and soft tissues and correlate these findings with pathologic features. We also review a wide spectrum of angiomatous syndromes.
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Brain
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Many different types of lesions are referred to as vascular malformations of the brain. Classic pathologic subtypes of these vascular malformations include arteriovenous malformations (AVMs), cavernous malformations, developmental venous anomalies (DVAs), telangiectasia, vein of Galen malformations, and mixed malformations (1,2).
Arteriovenous Malformations
The most familiar vascular malformations of the brain are AVMs. These lesions typically manifest in young adults, usually with a seizure or hemorrhage. AVMs form early during embryonic life as a result of direct communication of an artery with a vein without an intervening capillary bed (8). The nidus, or actual site of the abnormal communication, is often difficult to identify either radiologically or pathologically. Most of the lesion consists of dilated feeding arteries and dilated draining veins (Fig 1). Because the lesion develops simultaneously with the brain, there is usually neural tissue between these dilated arteries and veins. This tissue often becomes atrophic, gliotic, and even calcified. There may be associated atrophy of the brain tissue adjacent to the mass, which acts as a sump and a low-resistance pathway that "steals" blood from the normal tissue (8).
Because of the brisk flow through the shunt, AVMs manifest as a tangle of serpentine, curvilinear areas of low signal intensity at routine spin-echo MR imaging (9). MR angiography demonstrates dilated feeding arteries and multiple draining veins (Fig 2). The treatment for AVM varies depending on lesion location and size and the presence of complicating factors such as hemorrhage. Endovascular treatment, flow-directed embolization, surgical resection, and radiation therapy (including particle beam and stereotactic radiosurgery) have all been used (10).
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Figure 2. AVM. Axial maximum-intensity-projection MR angiogram from a time-of-flight sequence shows a dilated feeding left middle cerebral artery (thin arrow) and draining veins (thick arrows).
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Cavernous Malformations
Cavernous malformations (angioma, cavernoma, cavernous hemangioma) manifest in two different modes, may be inherited, and are typically multiple and bilateral, although they may also be solitary and sporadic (11). Cavernous angioma is basically a "blood sponge," a slow-flow lesion rather than a shunt. This lesion consists of variable-sized intercapillary vascular spaces, sinusoids, and larger cavernous spaces. However, unlike AVMs, cavernous angiomas have no intervening brain tissue between vascular spaces—hence the descriptive term blood sponge. In the past, cavernous angiomas could not be identified at routine angiography because of their slow flow and were typically referred to as "occult" or "cryptic" malformations (8).
Cavernous malformations frequently have a characteristic appearance at MR imaging, which is far more sensitive than angiography in detecting these lesions (12). Cavernous malformations typically have little or no mass effect, unless they are complicated by hemorrhage. Similarly, surrounding vasogenic edema does not occur unless there are hemorrhagic complications. Cavernous angiomas may have internal areas of thrombosis or hemorrhage. These blood products are typically of various ages, representing hemorrhage in various states of degradation. There may be conversion of hemoglobin to methemoglobin, which produces foci of hyperintensity on T1-weighted MR images. Hemosiderin may be cleared from the central area of a cavernous angioma and deposited around the periphery. This peripheral hemosiderin causes significant T2 shortening, producing a black "halo" around the lesion (Fig 3) (12).
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Figure 3a. Cavernous angioma. (a) Axial T2-weighted MR image of the brain shows a left frontal periventricular nodular lesion with a thick hypointense rim (arrow). (b) High-power photomicrograph (original magnification, x400; hematoxylin-eosin [H-E] stain) shows multiple vascular spaces of varying size. The vessels are stacked on top of each other with no intervening brain tissue.
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Figure 3b. Cavernous angioma. (a) Axial T2-weighted MR image of the brain shows a left frontal periventricular nodular lesion with a thick hypointense rim (arrow). (b) High-power photomicrograph (original magnification, x400; hematoxylin-eosin [H-E] stain) shows multiple vascular spaces of varying size. The vessels are stacked on top of each other with no intervening brain tissue.
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Developmental Venous Anomalies
DVAs may be isolated but have also been reported in association with cavernous angiomas (13). A DVA is a postcapillary malformation that classically appears as a "crown" of multiple small venules that converge on a larger venous trunk. The venous trunk is "transcortical" and usually drains into a dural sinus. The crown of veins that converge on the connecting trunk act as collecting veins that drain the capillaries from the affected volume (14). Hemorrhage from a DVA is unusual and in many cases is either discovered incidentally or is associated with a cavernous angioma. Surprisingly, spontaneous thrombosis of DVAs is the only variable associated with hemorrhagic infarction.
At MR imaging, there is usually a tubular flow void from the dilated transcortical vein with routine spin-echo pulse sequences (Fig 4). A DVA has been described as a "medusa head" and as a "palm tree" in which the dominant transcortical vein represents the trunk and the radiating crown of collecting veins represent the leaves.
Telangiectasia
Capillary telangiectasias are usually small, asymptomatic incidental findings. Most of these lesions are located in the brainstem and demonstrate slightly increased signal intensity on T2-weighted images, with low signal intensity on T2*-weighted images and ill-defined foci of enhancement after administration of gadopentetate dimeglumine (15). Capillary telangiectasias are dilated capillaries interspersed within normal brain parenchyma and lined with a thin layer of endothelium. The capillary walls contain no vascular smooth muscle or elastic fibers (15).
Vein of Galen Malformations
Vein of Galen malformations (VGMs) usually consist of a combination of lesions. Because the vein of Galen is a large vascular channel and is unsupported by surrounding tissue, any increase in venous pressure results in dilatation of the vein, often converting its shape from the normal cylindric to spheric—hence the nickname "vein of Galen aneurysm." Many causes have been suggested for the creation of a VGM (16), including hypoplasia or aplasia of the straight sinus, parenchymal AVMs, and dural fistulas.
The clinical manifestation of VGM is variable. Many patients present at birth with high-output cardiac failure, persistent patent ductus arteriosus, an audible cerebral bruit, a palpable thrill, and varying degrees of hydrocephalus.
Diagnosis at MR imaging is often straightforward. A rounded mass is identified in the appropriate location in the quadrigeminal plate cistern. The mass may demonstrate a pulsation artifact in the phase-encoding direction as well as a flow void with routine spin-echo pulse sequences (Fig 5). Treatment and outcome are variable. Significant factors that influence morbidity include clinical status, degree of shunting (in high-flow lesions), degree of hydrocephalus, and the nature of the primary cause of the VGM (16).
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Figure 5a. Vein of Galen malformation. (a) Sagittal spin-echo T1-weighted MR image shows a flow void in the vein of Galen (*). (b) Sagittal two-dimensional phase-contrast MR angiogram shows high-signal-intensity flow related to a venous malformation.
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Figure 5b. Vein of Galen malformation. (a) Sagittal spin-echo T1-weighted MR image shows a flow void in the vein of Galen (*). (b) Sagittal two-dimensional phase-contrast MR angiogram shows high-signal-intensity flow related to a venous malformation.
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Spine
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Spinal vascular malformations are reported to constitute approximately 3%–16% of all spinal masses (17). Pathologic subtypes include cavernous angiomas, capillary hemangiomas, and arteriovenous lesions (17).
Cavernous Angiomas
Cavernous angiomas affecting the spine are most often intramedullary. An autosomal dominant genetic defect with variable penetrance has been suggested as the causative factor in familial cases (18). Cavernous malformations of the spine are pathologically identical to intracranial cavernous angiomas. MR imaging findings are also characteristic, with a hypointense rim and heterogeneous signal intensity abnormalities on T1- and T2-weighted images representing blood products of various ages. Gliosis, edema, or syrinx adjacent to the lesion may cause abnormal signal intensity in the surrounding spinal cord parenchyma.
Capillary Hemangiomas
Capillary hemangiomas of the spine are rare but are most often extramedullary and either intradural or extradural. MR imaging may demonstrate a well-demarcated, strongly enhancing mass in the extramedullary space (19). Capillary hemangioma is difficult to differentiate from neurinoma or meningioma if there are no extensive retromedullary areas of signal void (Fig 6). At pathologic analysis, this lesion is virtually identical to soft-tissue capillary hemangioma.
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Figure 6a. Intradural capillary hemangioma. (a) Sagittal T2-weighted MR image shows a high-signal-intensity nodular extramedullary lesion (arrow) with serpiginous retromedullary areas of signal void (arrowheads). (b) Axial contrast-enhanced T1-weighted MR image shows the intradural extramedullary lesion (*) compressing the spinal cord to the right (arrow). (c) Coronal multiplanar reformatted MR angiogram shows the multilobular nodular lesion (arrow) with septa and serpiginous vessels. (d) Photomicrograph (original magnification, x200; H-E stain) reveals small vessels lined by flattened mature endothelium (arrows).
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Figure 6b. Intradural capillary hemangioma. (a) Sagittal T2-weighted MR image shows a high-signal-intensity nodular extramedullary lesion (arrow) with serpiginous retromedullary areas of signal void (arrowheads). (b) Axial contrast-enhanced T1-weighted MR image shows the intradural extramedullary lesion (*) compressing the spinal cord to the right (arrow). (c) Coronal multiplanar reformatted MR angiogram shows the multilobular nodular lesion (arrow) with septa and serpiginous vessels. (d) Photomicrograph (original magnification, x200; H-E stain) reveals small vessels lined by flattened mature endothelium (arrows).
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Figure 6c. Intradural capillary hemangioma. (a) Sagittal T2-weighted MR image shows a high-signal-intensity nodular extramedullary lesion (arrow) with serpiginous retromedullary areas of signal void (arrowheads). (b) Axial contrast-enhanced T1-weighted MR image shows the intradural extramedullary lesion (*) compressing the spinal cord to the right (arrow). (c) Coronal multiplanar reformatted MR angiogram shows the multilobular nodular lesion (arrow) with septa and serpiginous vessels. (d) Photomicrograph (original magnification, x200; H-E stain) reveals small vessels lined by flattened mature endothelium (arrows).
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Figure 6d. Intradural capillary hemangioma. (a) Sagittal T2-weighted MR image shows a high-signal-intensity nodular extramedullary lesion (arrow) with serpiginous retromedullary areas of signal void (arrowheads). (b) Axial contrast-enhanced T1-weighted MR image shows the intradural extramedullary lesion (*) compressing the spinal cord to the right (arrow). (c) Coronal multiplanar reformatted MR angiogram shows the multilobular nodular lesion (arrow) with septa and serpiginous vessels. (d) Photomicrograph (original magnification, x200; H-E stain) reveals small vessels lined by flattened mature endothelium (arrows).
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Arteriovenous Lesions
The most common spinal vascular malformations are arteriovenous lesions, either AVMs or arteriovenous fistulas. AVMs consist of a nidus with arterial supply and dilated draining veins. These lesions may be either extradural-intradural or entirely intradural (Fig 7). Arteriovenous fistulas consist of a direct arteriovenous shunt that drains through an engorged draining vein and may be either extradural or intradural (20). MR imaging findings may include diffuse abnormal signal intensity on T2-weighted images; however, this finding is nonspecific and may also be seen in inflammatory, demyelinating, and neoplastic conditions involving the spinal cord. The hallmark of the diagnosis is the presence of dilated veins along the dorsal surface of the cord. In such cases, the combined use of MR angiography and standard MR imaging of the spine improves localization of the fistulas at specific vertebral levels (21).
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Figure 7a. AVM of the spinal cord. (a) Sagittal T2-weighted MR image shows flow voids along the surface of the spinal cord (arrowheads) and a serpentine vascular structure with flow voids at the C6-7 level (arrow). (b) Sagittal contrast-enhanced three-dimensional MR angiogram demonstrates a nidus (thick arrow) with a large feeding vessel (thin arrow).
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Figure 7b. AVM of the spinal cord. (a) Sagittal T2-weighted MR image shows flow voids along the surface of the spinal cord (arrowheads) and a serpentine vascular structure with flow voids at the C6-7 level (arrow). (b) Sagittal contrast-enhanced three-dimensional MR angiogram demonstrates a nidus (thick arrow) with a large feeding vessel (thin arrow).
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Liver
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Hemangioma of the liver is exceedingly common, affecting up to 20% of adults (22). These lesions are commonly seen incidentally at imaging. Most lesions are clinically silent, becoming symptomatic only if they are large, compress adjacent structures, or rupture (22). At gross examination, a typical hemangioma appears as a spongy cystic tumor (Fig 8c). At histologic analysis, hemangiomas consist of vascular channels with a single layer of benign endothelial cells (Fig 8d). A peripheral location is most common. Hemangiomas have high signal intensity secondary to their water content and, subsequently, a prolonged relaxation time at T2-weighted MR imaging (Fig 8a). Hemangiomas become brighter at T2-weighted imaging, whereas metastases demonstrate some loss in signal intensity (23). At T1-weighted MR imaging, a slow, centripetal pattern of peripheral enhancement after administration of gadolinium-based contrast material is most specific for hemangioma (Fig 8b) (24). Less frequently, hemangiomas may have atypical features such as heterogeneity, rapid enhancement, calcification, thrombosis, hemorrhage- and fluid-fluid levels, and fibrosis (25,26).
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Figure 8a. Hepatic cavernous hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lobulated tumor with central necrosis (*). (b) Axial contrast-enhanced T1-weighted MR image shows the tumor with the typical centripetal pattern of peripheral enhancement (arrows). (c) Photograph of the gross specimen shows the vascular cystic spaces (arrows) of the tumor (hemangioma). (d) Photomicrograph (original magnification, x200; H-E stain) shows dilated vascular spaces filled with blood and lined by a single layer of endothelial cells (arrows).
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Figure 8b. Hepatic cavernous hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lobulated tumor with central necrosis (*). (b) Axial contrast-enhanced T1-weighted MR image shows the tumor with the typical centripetal pattern of peripheral enhancement (arrows). (c) Photograph of the gross specimen shows the vascular cystic spaces (arrows) of the tumor (hemangioma). (d) Photomicrograph (original magnification, x200; H-E stain) shows dilated vascular spaces filled with blood and lined by a single layer of endothelial cells (arrows).
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Figure 8c. Hepatic cavernous hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lobulated tumor with central necrosis (*). (b) Axial contrast-enhanced T1-weighted MR image shows the tumor with the typical centripetal pattern of peripheral enhancement (arrows). (c) Photograph of the gross specimen shows the vascular cystic spaces (arrows) of the tumor (hemangioma). (d) Photomicrograph (original magnification, x200; H-E stain) shows dilated vascular spaces filled with blood and lined by a single layer of endothelial cells (arrows).
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Figure 8d. Hepatic cavernous hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lobulated tumor with central necrosis (*). (b) Axial contrast-enhanced T1-weighted MR image shows the tumor with the typical centripetal pattern of peripheral enhancement (arrows). (c) Photograph of the gross specimen shows the vascular cystic spaces (arrows) of the tumor (hemangioma). (d) Photomicrograph (original magnification, x200; H-E stain) shows dilated vascular spaces filled with blood and lined by a single layer of endothelial cells (arrows).
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Spleen
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Splenic hemangioma, although rare, is the most common primary neoplasm of the spleen. This lesion is usually asymptomatic and discovered serendipitously. At microscopic examination, splenic hemangiomas show the same proliferation of variable-sized vascular channels as do liver hemangiomas (27). At MR imaging, hemangiomas of the liver and spleen typically demonstrate similar signal intensity characteristics and enhancement patterns (28). Calcium, cysts, necrosis, or fibrosis (29) result in atypical patterns at MR imaging (Fig 9).
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Figure 9. Splenic epithelioid hemangioma. Axial T2-weighted MR image shows a heterogeneous, low-signal-intensity splenic mass (solid arrow) with hypointense radial lines due to fibrosis, similar to the spokes of a wheel (open arrows).
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Bone
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Vascular lesions of bone are commonly seen incidentally at radiology. The most common sites of involvement are the vertebrae and skull (30). The majority of lesions in the spine involve the vertebral body. Vertebral hemangiomas are usually small and asymptomatic, although they may be symptomatic, with local or radicular pain or spinal cord compression secondary to epidural hemorrhage or soft-tissue extension (31). In general, bone hemangiomas do not represent a radiologic diagnostic problem. At MR imaging, vertebral hemangiomas demonstrate the classic vertical trabecular or radiating pattern of thickening seen at radiography, with high signal intensity on T1- and T2-weighted images due to the presence of intratumoral fat (Fig 10). Other atypical hemangiomas such as epithelioid hemangioma and epithelioid hemangioendothelioma may demonstrate a heterogeneous pattern with mixed signal intensity on T1- and T2-weighted MR images that reflects the absence of fat and the presence of inflammatory infiltrate (Fig 11).
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Figure 11a. Vertebral hemangioendothelioma. (a) Axial T1-weighted MR image shows a vertebral hemangioendothelioma with the typical trabecular low-signal-intensity pattern (arrow). (b) High-power photomicrograph (original magnification, x400; H-E stain) shows endothelial cells (arrows) and inflammatory cells (arrowheads).
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Figure 11b. Vertebral hemangioendothelioma. (a) Axial T1-weighted MR image shows a vertebral hemangioendothelioma with the typical trabecular low-signal-intensity pattern (arrow). (b) High-power photomicrograph (original magnification, x400; H-E stain) shows endothelial cells (arrows) and inflammatory cells (arrowheads).
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Soft Tissue
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Hemangioma is the most frequently encountered vascular soft-tissue abnormality. It is estimated that hemangiomas comprise 7% of all benign soft-tissue tumors (32). The most commonly used classification system is based on clinical findings, cellular turnover, and histologic features (3). With this system, vascular anomalies are separated into two major groups: hemangiomas and vascular malformations (Table). Infantile hemangiomas tend to be small or absent at birth. Shortly after birth, they enter a proliferative phase with rapid growth that may last several months, followed by a stationary period and, finally, a period of involution. In contrast, vascular malformations are always present at birth and enlarge in proportion to growth. They do not involute and remain present throughout life. Vascular malformations are categorized as lymphatic, capillary, venous, arteriovenous, or mixed malformations on the basis of their histologic features (3). A more pertinent issue is the classification of vascular malformations as either high- or low-flow on the basis of hemodynamic flow characteristics (Table) (5).
MR imaging is a useful noninvasive technique for the examination of vascular malformations because of its superior soft-tissue contrast and multiplanar capability. MR imaging plays a major role in diagnosing, characterizing, and determining the extent of the lesions. The MR imaging appearance of soft-tissue vascular anomalies correlates well with their biologic classification (33).
MR imaging for soft-tissue vascular anomalies should include spin-echo T1- and T2-weighted, fat-saturated T2-weighted, and gradient-echo sequences. The addition of gadolinium-enhanced dynamic MR angiography is helpful in characterizing the arterial or venous nature of these anomalies (7,34).
In the following sections, we discuss localized vascular malformations (hemangiomas), hemangiopericytomas, hemangioendotheliomas, and glomus tumors.
Hemangiomas
Localized vascular malformations, or hemangiomas, are usually located superficially but may involve deep structures such as skeletal muscle. Deep-seated lesions more frequently present a diagnostic dilemma and necessitate radiologic assessment. Deep-seated hemangiomas are usually intramuscular, although synovial hemangiomas may also occur (4).
MR imaging findings in hemangioma are frequently diagnostic. On T2-weighted images, hemangiomas generally appear as multiple high-signal-intensity lobules that resemble a bunch of grapes (Fig 12c). This appearance is due to cavernous or cystic vascular spaces containing stagnant blood. Fluid-fluid levels can also be noted within these spaces (35). Punctate or reticular low-signal-intensity areas may be present, representing fibrous tissue, fast flow within vessels, or foci of calcification (Fig 13). Areas of thrombosis appear as circular low-signal-intensity areas at MR imaging (Fig 14), similar to phleboliths. In these cases, conventional radiography or computed tomography (CT) is helpful in diagnosing soft-tissue hemangioma (Fig 12b). On T1-weighted MR images, the signal intensity of these lesions is usually intermediate between that of muscle and fat. In some hemangiomas, peripheral high-signal-intensity areas representing intralesional fat are noted on T1-weighted images (Fig 12a).
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Figure 12a. Intramuscular hemangioma of the calf. (a) Sagittal T1-weighted MR image shows a soft-tissue mass with intermediate signal intensity relative to muscle, along with an overgrowth of fat (arrow) and punctate low-signal-intensity areas (arrowheads). (b) Radiograph demonstrates phleboliths (arrow), which account for the punctate low-signal-intensity areas seen at T1-weighted MR imaging. (c) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with septa (arrows). (d) High-power photomicrograph (original magnification, x400; H-E stain) demonstrates muscle fibers with proliferation of vessels of different sizes (arrows), along with prominent endothelium and adipocytes (arrowheads).
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Figure 12b. Intramuscular hemangioma of the calf. (a) Sagittal T1-weighted MR image shows a soft-tissue mass with intermediate signal intensity relative to muscle, along with an overgrowth of fat (arrow) and punctate low-signal-intensity areas (arrowheads). (b) Radiograph demonstrates phleboliths (arrow), which account for the punctate low-signal-intensity areas seen at T1-weighted MR imaging. (c) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with septa (arrows). (d) High-power photomicrograph (original magnification, x400; H-E stain) demonstrates muscle fibers with proliferation of vessels of different sizes (arrows), along with prominent endothelium and adipocytes (arrowheads).
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Figure 12c. Intramuscular hemangioma of the calf. (a) Sagittal T1-weighted MR image shows a soft-tissue mass with intermediate signal intensity relative to muscle, along with an overgrowth of fat (arrow) and punctate low-signal-intensity areas (arrowheads). (b) Radiograph demonstrates phleboliths (arrow), which account for the punctate low-signal-intensity areas seen at T1-weighted MR imaging. (c) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with septa (arrows). (d) High-power photomicrograph (original magnification, x400; H-E stain) demonstrates muscle fibers with proliferation of vessels of different sizes (arrows), along with prominent endothelium and adipocytes (arrowheads).
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Figure 12d. Intramuscular hemangioma of the calf. (a) Sagittal T1-weighted MR image shows a soft-tissue mass with intermediate signal intensity relative to muscle, along with an overgrowth of fat (arrow) and punctate low-signal-intensity areas (arrowheads). (b) Radiograph demonstrates phleboliths (arrow), which account for the punctate low-signal-intensity areas seen at T1-weighted MR imaging. (c) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with septa (arrows). (d) High-power photomicrograph (original magnification, x400; H-E stain) demonstrates muscle fibers with proliferation of vessels of different sizes (arrows), along with prominent endothelium and adipocytes (arrowheads).
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Figure 13a. Submandibular hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lesion with flow voids representing vessels of different sizes (arrows), along with multiple low-signal-intensity foci (arrowheads). (b) CT scan demonstrates phleboliths (arrowheads), which account for the low-signal-intensity foci seen at MR imaging.
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Figure 13b. Submandibular hemangioma. (a) Axial T2-weighted MR image shows a high-signal-intensity lesion with flow voids representing vessels of different sizes (arrows), along with multiple low-signal-intensity foci (arrowheads). (b) CT scan demonstrates phleboliths (arrowheads), which account for the low-signal-intensity foci seen at MR imaging.
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Figure 14a. Cavernous hemangioma of the foot. (a) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with low-signal-intensity foci (arrowheads) that represent thrombosis. (b) Low-power photomicrograph (original magnification, x40; H-E stain) shows dilated intraluminal vessels with thrombosis (arrows).
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Figure 14b. Cavernous hemangioma of the foot. (a) Axial T2-weighted MR image demonstrates a high-signal-intensity lesion with low-signal-intensity foci (arrowheads) that represent thrombosis. (b) Low-power photomicrograph (original magnification, x40; H-E stain) shows dilated intraluminal vessels with thrombosis (arrows).
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Although hemangiomas are often heterogeneous, small capillary hemangiomas can demonstrate homogeneous signal intensity and high perfusion (Fig 15), whereas cavernous hemangiomas demonstrate low perfusion (7).
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Figure 15a. Capillary hemangioma of the thigh. (a) Coronal maximum-intensity-projection MR angiogram shows a contrast-enhanced microlobular lesion in the left thigh (arrow). (b) Graph of a time-signal intensity curve demonstrates a fast perfusion-enhancement pattern. (c) Low-power photomicrograph (original magnification, x40; H-E stain) shows capillaries of varying sizes (arrows).
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Figure 15b. Capillary hemangioma of the thigh. (a) Coronal maximum-intensity-projection MR angiogram shows a contrast-enhanced microlobular lesion in the left thigh (arrow). (b) Graph of a time-signal intensity curve demonstrates a fast perfusion-enhancement pattern. (c) Low-power photomicrograph (original magnification, x40; H-E stain) shows capillaries of varying sizes (arrows).
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Figure 15c. Capillary hemangioma of the thigh. (a) Coronal maximum-intensity-projection MR angiogram shows a contrast-enhanced microlobular lesion in the left thigh (arrow). (b) Graph of a time-signal intensity curve demonstrates a fast perfusion-enhancement pattern. (c) Low-power photomicrograph (original magnification, x40; H-E stain) shows capillaries of varying sizes (arrows).
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MR imaging can be used to classify vascular malformations as either low-flow or high-flow lesions, especially when combined with dynamic contrast-enhanced MR angiography (5,7,33). Slow-flow vascular malformations (venous, capillary, cavernous, or mixed) contain large spaces with fine serpentine structures that are usually oriented along the long axis of the extremities, follow a neurovascular bundle, and are sometimes multifocal (36). High-flow vascular malformations show more prominent serpentine vessels. Faster flow may manifest as areas of flow void with all pulse sequences (5,7,36). Differentiation between different types of low-flow vascular malformations is often not possible at conventional MR imaging because the distinctive features of these lesions are based on vessel lumen size and wall thickness (4). Capillary and cavernous hemangiomas are distinguished by the fact that most of their vessels are thin walled, whereas venous malformations are thick walled, although at pathologic analysis some venous malformations may have areas that are indistinguishable from cavernous hemangioma. These types of lesions are designated as mixed hemangiomas (4).
Synovial hemangioma is rare and almost always involves the knee joint, with patients presenting with pain, swelling, and joint effusion. The most common site of involvement is the suprapatellar pouch. MR imaging frequently allows a specific diagnosis (37). These lesions appear as a poorly marginated, lobulated mass with intermediate signal intensity on T1-weighted images, although they may contain hyperintense areas that represent intratumoral fat (Fig 16a). On T2-weighted images, these lesions have high signal intensity, with low-signal-intensity linear structures throughout the mass representing fibrofatty septa or vascular channels (Fig 16b) (38). Synovial hemangioma shows intense and heterogeneous contrast enhancement (37). These lesions can demonstrate extraarticular involvement and cause pressure erosions of adjacent bone (37,38).
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Figure 16a. Synovial hemangioma of the knee. (a) Axial T1-weighted MR image shows an intermediate-signal-intensity lesion in the suprapatellar pouch (arrow) containing areas of high signal intensity. (b) On a corresponding axial fat-suppressed T2-weighted MR image, the lesion demonstrates the characteristic circular-linear pattern (arrow). (c) Photomicrograph (original magnification, x200; H-E stain) depicts the synovial membrane with vascular proliferation (arrows) and vacuoles in the subjacent tissue (arrowheads).
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Figure 16b. Synovial hemangioma of the knee. (a) Axial T1-weighted MR image shows an intermediate-signal-intensity lesion in the suprapatellar pouch (arrow) containing areas of high signal intensity. (b) On a corresponding axial fat-suppressed T2-weighted MR image, the lesion demonstrates the characteristic circular-linear pattern (arrow). (c) Photomicrograph (original magnification, x200; H-E stain) depicts the synovial membrane with vascular proliferation (arrows) and vacuoles in the subjacent tissue (arrowheads).
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Figure 16c. Synovial hemangioma of the knee. (a) Axial T1-weighted MR image shows an intermediate-signal-intensity lesion in the suprapatellar pouch (arrow) containing areas of high signal intensity. (b) On a corresponding axial fat-suppressed T2-weighted MR image, the lesion demonstrates the characteristic circular-linear pattern (arrow). (c) Photomicrograph (original magnification, x200; H-E stain) depicts the synovial membrane with vascular proliferation (arrows) and vacuoles in the subjacent tissue (arrowheads).
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Hemangiopericytomas
Hemangiopericytomas are uncommon tumors that arise from the cells of Zimmerman that are located around vessels. They are tumors of intermediate aggressiveness that have both benign and malignant forms. Hemangiopericytomas commonly involve the lower extremities, pelvis, and retroperitoneum (4). MR imaging findings are not specific and usually consist of a well- to fairly well-circumscribed solitary mass with intermediate signal intensity on T1-weighted images and mild hyperintensity on T2-weighted images (Fig 17). Some hemangiopericytomas may show prominent serpentine vessels, a finding that reflects rich tumor vascularization. The presence of intratumoral necrosis indicates malignancy (39).
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Figure 17a. Hemangiopericytoma of the neck. (a) Axial T2-weighted MR image shows a mildly hyperintense lesion in the right multifidus muscle (arrow). (b) High-power photomicrograph (original magnification, x400; reticulin stain) shows a reticulin meshwork surrounding packed pericytes (arrows).
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Figure 17b. Hemangiopericytoma of the neck. (a) Axial T2-weighted MR image shows a mildly hyperintense lesion in the right multifidus muscle (arrow). (b) High-power photomicrograph (original magnification, x400; reticulin stain) shows a reticulin meshwork surrounding packed pericytes (arrows).
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Hemangioendotheliomas
Hemangioendotheliomas are intermediately aggressive vascular neoplasms of the endothelial cells. Both hemangiomas and hemangioendotheliomas can be of the epithelioid (histiocytoid) subtype when the endothelial cells have an epithelial appearance (4). Soft-tissue hemangioendothelioma usually involves the deep structures of the extremities but may develop in the dermis or subcutaneous tissue (Fig 18). The MR imaging characteristics are not specific, and the appearance may be identical to that of a solitary hemangioma (Fig 18).
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Figure 18a. Epithelioid hemangioendothelioma of the hand. (a, b) Axial T2-weighted (a) and sagittal T1-weighted (b) MR images show a nodular lesion of the hypothenar region (arrow). The lesion demonstrates moderately high signal intensity on the T2-weighted image and intermediate signal intensity on the T1-weighted image. (c) High-power photomicrograph (original magnification, x400; H-E stain) shows strands of fusiform endothelial cells (arrows) and canalized vascular channels (*).
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Figure 18b. Epithelioid hemangioendothelioma of the hand. (a, b) Axial T2-weighted (a) and sagittal T1-weighted (b) MR images show a nodular lesion of the hypothenar region (arrow). The lesion demonstrates moderately high signal intensity on the T2-weighted image and intermediate signal intensity on the T1-weighted image. (c) High-power photomicrograph (original magnification, x400; H-E stain) shows strands of fusiform endothelial cells (arrows) and canalized vascular channels (*).
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Figure 18c. Epithelioid hemangioendothelioma of the hand. (a, b) Axial T2-weighted (a) and sagittal T1-weighted (b) MR images show a nodular lesion of the hypothenar region (arrow). The lesion demonstrates moderately high signal intensity on the T2-weighted image and intermediate signal intensity on the T1-weighted image. (c) High-power photomicrograph (original magnification, x400; H-E stain) shows strands of fusiform endothelial cells (arrows) and canalized vascular channels (*).
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Glomus Tumors
Glomus tumors are benign neoplasms that derive from the neuromyoarterial glomus bodies (4). They are located in the subungual region, digits, and palms. Glomus tumors cause joint tenderness and pain. MR imaging findings are variable, but most tumors are markedly hyperintense relative to subcutaneous fat on T2-weighted images (Fig 19) (40). On T1-weighted images, the tumor ranges from hypo- to hyperintense depending on the histologic cellular pattern (vascular, myxoid, or solid) (40).
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Figure 19a. Glomus tumor of the finger. (a) Sagittal T2-weighted MR image shows a nodular soft-tissue mass with high signal intensity (*) in the palmar aspect of the distal phalanx. (b) Photomicrograph (original magnification, x200; H-E stain) shows glomic arterioles (*) separated by hyalinized fibers.
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Figure 19b. Glomus tumor of the finger. (a) Sagittal T2-weighted MR image shows a nodular soft-tissue mass with high signal intensity (*) in the palmar aspect of the distal phalanx. (b) Photomicrograph (original magnification, x200; H-E stain) shows glomic arterioles (*) separated by hyalinized fibers.
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Angiomatous Syndromes
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Angiomatous syndromes include angiomatosis, Gorham disease, Maffucci syndrome, Klippel-Trénaunay-Weber syndrome, Osler-Weber-Rendu disease, Kasabach-Merritt syndrome, Sturge-Weber syndrome, and von Hippel–Lindau disease.
Angiomatosis
Angiomatosis is defined as diffuse infiltration of bone or soft tissue by hemangiomatous or lymphangiomatous lesions (30). Predominant involvement of osseous structures often follows a relatively indolent course, but extensive soft-tissue and visceral involvement carries a poorer prognosis (41). When bone is involved extensively, the term cystic angiomatosis has been applied. The MR imaging appearance of angiomatosis may be identical to that of solitary angiomatous lesions (42). At MR imaging, cystic angiomatous lesions may demonstrate a hypointense fine trabecular pattern on T1-weighted images with homogeneous contrast enhancement (Fig 20). At histologic analysis, cystic angiomatosis is indistinguishable from cavernous hemangioma, capillary hemangioma, or lymphangioma (43).
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Figure 20a. Cystic angiomatosis. (a) Sagittal contrast-enhanced T1-weighted MR image shows multiple enhancing lesions (arrows) attached to the dura mater and eroding the inner table. (b) Coronal T1-weighted MR image of the sacrum shows the iliac bones with diffuse low signal intensity (arrows). (c) Photomicrograph (original magnification, x100; H-E stain) demonstrates multiple dilated vascular canals in the bone marrow (arrows). These canals are indistinguishable from cavernous or capillary hemangiomas.
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Figure 20b. Cystic angiomatosis. (a) Sagittal contrast-enhanced T1-weighted MR image shows multiple enhancing lesions (arrows) attached to the dura mater and eroding the inner table. (b) Coronal T1-weighted MR image of the sacrum shows the iliac bones with diffuse low signal intensity (arrows). (c) Photomicrograph (original magnification, x100; H-E stain) demonstrates multiple dilated vascular canals in the bone marrow (arrows). These canals are indistinguishable from cavernous or capillary hemangiomas.
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Figure 20c. Cystic angiomatosis. (a) Sagittal contrast-enhanced T1-weighted MR image shows multiple enhancing lesions (arrows) attached to the dura mater and eroding the inner table. (b) Coronal T1-weighted MR image of the sacrum shows the iliac bones with diffuse low signal intensity (arrows). (c) Photomicrograph (original magnification, x100; H-E stain) demonstrates multiple dilated vascular canals in the bone marrow (arrows). These canals are indistinguishable from cavernous or capillary hemangiomas.
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Gorham Disease
Gorham disease (massive osteolysis of Gorham, or disappearing bone disease) is a rare condition characterized by nonmalignant proliferation of vascular or lymphatic structures of bone, resulting in progressive bone destruction and often extending into surrounding soft tissues (30). The MR imaging characteristics of Gorham disease are variable. Signal intensity on T1- and T2-weighted images is likely to reflect the degree of neovascular progression and fibrosis. Concurrent fibrosis has low signal intensity with both pulse sequences, creating the heterogeneous appearance seen within the involved tissue. The pattern of enhancement is also variable, which could be attributed to the variable composition of hemangiomatous or lymphangiomatous tissue with fibrosis. MR imaging can help accurately determine the extent of disease, including the presence of soft-tissue involvement (44).
Maffucci Syndrome
Maffucci syndrome is characterized by multiple enchondromas and soft-tissue cavernous hemangiomas. The hands and feet often show the greatest extent of involvement (30). Malignant transformation occurs in both enchondromas and soft-tissue hemangiomas (4). MR imaging in Maffucci syndrome may be helpful in diagnosing and localizing deep-seated hemangiomas (45).
Klippel-Trénaunay-Weber Syndrome
Klippel-Trénaunay-Weber syndrome consists of the triad of cutaneous hemangioma, bone and soft-tissue hypertrophy, and varicose veins (30). The syndrome is usually unilateral and involves the lower extremity. Arteriovenous fistula may also be present, a manifestation that is often called Parkes-Weber syndrome (Fig 21). MR imaging, especially in combination with MR angiography, helps characterize the different vascular malformations and identify and delineate lesion extension throughout the extremity (Fig 21) (46).
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Figure 21. Klippel-Trénaunay-Parkes-Weber syndrome. Maximum-intensity-projection subtraction MR angiogram shows an AVM of the left calf (thin arrow) that drains into a persistent sciatic vein (thick arrow).
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Osler-Weber-Rendu Disease
Osler-Weber-Rendu syndrome, or hereditary hemorrhagic telangiectasia, is caused by a systemic fibrovascular dysplasia of all vessels (30). Osseous involvement is quite rare but ranges from classic vertebral hemangioma to calvarial angiomatosis and synovial hemangioma. MR imaging may be used to reveal cerebral AVMs (47).
Kasabach-Merritt Syndrome
Kasabach-Merritt syndrome is a rare complication of large hemangiomas with thrombocytopenia and purpura (48). This syndrome is a coagulopathy consisting of intravascular coagulation, clotting, and fibrinolysis within the hemangioma. The literature suggests that a specific histologic pattern of vascular tumors is responsible for Kasabach-Merritt syndrome (49). Panow et al (50) described the MR imaging (and CT) findings in a hemangioma in Kasabach-Merritt syndrome.
Sturge-Weber Syndrome
Sturge-Weber syndrome is a neurocutaneous syndrome (phakomatosis) characterized by facial port-wine nevus, seizures, glaucoma, buphthalmos, and mental retardation (51). MR imaging findings in Sturge-Weber syndrome consist of a leptomeningeal angiomatous malformation and parenchymal venous anomalies that enhance after contrast material administration (52). The adjunct use of MR angiography can help evaluate centripetal venous drainage and the possible progressive occlusion of deep veins (53).
Von Hippel–Lindau Disease
Von Hippel–Lindau disease is a hereditary phakomatosis characterized by hemangioblastomas of the cerebellum, brainstem, and spinal cord; retinal angiomas; renal and pancreatic cysts; renal cell carcinomas; and pheochromocytomas (51). MR imaging is the imaging modality of choice for evaluating patients with von Hippel–Lindau disease because it can help characterize lesions of the cerebellum, spine, and viscera in a single procedure (54). Hemangioblastomas of the cerebellum usually appear as a cystic tumor with a mural nodule, with marked contrast enhancement and sometimes a visible flow void from the feeding and draining vessels (55). Large hemangioblastomas are mostly heterogeneous on T2-weighted and contrast-enhanced images, whereas smaller ones tend to be homogeneous on T1- and T2-weighted images and contrast-enhanced images, with or without a cystic component (Fig 22) (56).
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Figure 22a. Intradural hemangioblastoma. (a) Sagittal T1-weighted MR image shows a small intradural hemangioblastoma with the typical homogeneous nodular enhancement pattern. (b) High-power photomicrograph (original magnification, x400; H-E stain) reveals a proliferation of fusiform cells (arrows) with interlaced blood material (arrowheads).
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Figure 22b. Intradural hemangioblastoma. (a) Sagittal T1-weighted MR image shows a small intradural hemangioblastoma with the typical homogeneous nodular enhancement pattern. (b) High-power photomicrograph (original magnification, x400; H-E stain) reveals a proliferation of fusiform cells (arrows) with interlaced blood material (arrowheads).
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Conclusions
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Vascular anomalies may be categorized as either infantile hemangiomas or vascular malformations. The combined use of conventional MR imaging and MR angiography allows characterization of vascular lesions on the basis of pathologic features and hemodynamic flow characteristics. Vascular malformations appear at MR imaging with characteristic patterns that vary depending on what organ or system is involved (eg, central nervous system, musculoskeletal system, liver and spleen). Familiarity with the MR imaging findings that can help differentiate these lesions is essential to confirm the suspected diagnosis, determine the extent of the anomaly, classify the lesion appropriately, and document associated abnormalities.
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Footnotes
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2** indicates multiple body systems. 
Abbreviations: AVM = arteriovenous malformation,
DVA = developmental venous anomaly,
H-E = hematoxylin-eosin,
VGM = vein of Galen malformation
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K. M. Elsayes, C. O. Menias, J. R. Dillman, J. F. Platt, J. M. Willatt, and J. P. Heiken
Vascular Malformation and Hemangiomatosis Syndromes: Spectrum of Imaging Manifestations
Am. J. Roentgenol.,
May 1, 2008;
190(5):
1291 - 1299.
[Abstract]
[Full Text]
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P. T. Liu
Radiological Reasoning: Acutely Painful Swollen Finger
Am. J. Roentgenol.,
March 1, 2007;
188(3_Supplement):
S13 - S17.
[Abstract]
[Full Text]
[PDF]
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V. R. Stewart, S. Sriprasad, S. Pomplun, K. Walsh, and P. S. Sidhu
Sonographic Features of a Spermatic Cord Capillary Hemangioma
J. Ultrasound Med.,
January 1, 2007;
26(1):
139 - 142.
[Full Text]
[PDF]
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A. G. Blum, J.-P. Zabel, R. Kohlmann, T. Batch, K. Barbara, X. Zhu, G. Dautel, and F. Dap
Pathologic Conditions of the Hypothenar Eminence: Evaluation with Multidetector CT and MR Imaging.
RadioGraphics,
July 1, 2006;
26(4):
1021 - 1044.
[Abstract]
[Full Text]
[PDF]
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A. A. Shi, D. Georgian-Smith, L. D. Cornell, E. A. Rafferty, M. Staffa, K. Hughes, and D. B. Kopans
Radiological Reasoning: Male Breast Mass with Calcifications
Am. J. Roentgenol.,
December 1, 2005;
185(6_Supplement):
S205 - S210.
[Abstract]
[Full Text]
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Abstract
LEARNING OBJECTIVES FOR TEST...
