Hemangioma

Look For First

Markedly T2-hyperintense lobulated mass or serpiginous tubular channels in the buccal space lateral to the buccinator
Presence of internal rounded or serpiginous low-signal phleboliths on T2 or GRE/SWI sequences
Progressive venous enhancement pattern on dynamic contrast-enhanced MRI rather than early avid enhancement

Key Image Findings

On T1-weighted MRI: lesion is usually low-to-intermediate signal relative to fat, with heterogeneous higher-signal foci indicating hemorrhage or thrombosis.
On T2/STIR: markedly hyperintense lobules or serpiginous tubular venous channels, often described as a 'bunch of grapes' appearance with internal low-signal septa or phleboliths.
On postcontrast MRI: progressive venous filling and delayed heterogeneous enhancement; thrombosed components do not enhance.
On GRE/SWI: susceptibility-related low-signal blooming from phleboliths or blood products aids detection of hemosiderin and thrombus.
On CT: lobulated soft-tissue lesion near muscle attenuation before contrast, with rounded calcified phleboliths when present.
On Doppler ultrasound: compressible vascular spaces with slow or weak venous flow; absence of Doppler signal does not exclude the lesion.
Anatomic location: epicenter is within cheek fat lateral to the buccinator and anterior to the masseter, with possible extension into subcutaneous tissues, muscles, or adjacent facial spaces.
Phleboliths are a particularly useful discriminator to distinguish venous malformations from true hemangiomas and lymphatic malformations, though their absence does not exclude venous malformation.

Differential Diagnosis

Lymphatic malformation: multicystic architecture with fluid-fluid levels and predominantly septal/peripheral rather than diffuse internal enhancement; mixed venolymphatic lesions can overlap.
Arteriovenous malformation (AVM): numerous serpiginous flow voids, enlarged feeding arteries and early draining veins, typically without a substantial solid mass component.
True infantile hemangioma: discrete solid vascular mass with early avid enhancement and high-flow vessels, particularly with characteristic infantile growth history and proliferation followed by involution.
Pleomorphic adenoma: circumscribed solid enhancing mass that can be very T2 bright but lacks characteristic venous-channel architecture and phleboliths.
Abscess: rim-enhancing fluid collection with surrounding inflammatory change and possible dental source rather than enhancing venous channels.

Discussion

Terminology distinction: slow-flow lesions with characteristic venous-channel morphology should be termed venous malformations (developmental vascular malformations) rather than hemangiomas (proliferative vascular tumors) to accurately reflect vascular biology and clinical behavior.

Venous malformations are often longstanding, soft, compressible, and nonpulsatile, whereas true infantile hemangiomas appear in the first weeks of life, proliferate, and then involute over time.

The strongest diagnostic combination for venous malformation is venous-channel morphology, very high T2 signal, delayed enhancement, and phleboliths—not T2 hyperintensity alone.

Phleboliths (rounded calcifications) strongly support the diagnosis of venous malformation and help distinguish it from true hemangiomas where they are uncharacteristic.

Dynamic contrast-enhanced MRI and Doppler ultrasound are helpful when flow characteristics remain uncertain, particularly to confirm slow-flow patterns and exclude high-flow shunting.

Clinical course and imaging evolution matter: developmental lesions often present as longstanding masses, whereas true hemangiomas demonstrate dramatic early enhancement during the proliferative phase.

Reporting Pearls

Document the specific imaging combination present (venous channels, T2 signal intensity, enhancement pattern, phleboliths, and anatomic location) using the template: "Lobulated vascular lesion centered in the [right/left] buccal space, demonstrating markedly T2-hyperintense venous channels, progressive enhancement, and internal phleboliths—findings favor a slow-flow venous malformation." Include caveats when dynamic imaging was not performed or features remain indeterminate.

Pitfalls

Do not use 'hemangioma' and 'venous malformation' interchangeably; the former is a proliferative tumor while the latter is a developmental malformation with distinct biological behavior and enhancement kinetics.
Absence of phleboliths does not exclude venous malformation; phleboliths are strongly supportive but not required for diagnosis.
Do not confuse rounded low-signal phleboliths with serpiginous high-flow vascular flow voids; each has different implications for shunting and treatment.
Avoid claiming early avid or progressive enhancement on a single postcontrast acquisition; true assessment of enhancement pattern requires dynamic imaging, and static postcontrast images alone are insufficient to exclude high-flow lesions.

Hemangioma

Key Images

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