A hemangioma is the most common type of benign vascular tumor found in infancy, characterized by an abnormal proliferation of blood vessel cells. While these growths are not cancerous, their size and location can sometimes cause concern, especially for parents of newborns. Ultrasound imaging is routinely employed as the primary, non-invasive method to confirm the diagnosis, determine the tumor’s exact location and size, and help guide initial management decisions. This diagnostic process provides clinicians with a clear picture of the lesion’s internal structure and blood flow patterns.
Understanding Hemangiomas
Hemangiomas are generally divided into two main categories based on when they appear and their natural life cycle. Infantile Hemangiomas (IH) are typically absent at birth or appear as a faint mark, becoming visible within the first few weeks of life. These lesions are well-known for their unique triphasic natural history, which dictates their growth pattern over time.
The first stage is the proliferative phase, marked by rapid growth, which usually peaks between one and three months of age, with most growth concluding by five months. This is followed by a plateau phase where the lesion stabilizes in size before entering the third stage, the involution phase. During involution, the hemangioma slowly regresses, which can take several years, often leaving behind some residual fibrofatty tissue or skin changes. Congenital Hemangiomas (CH), in contrast, are fully formed and present at the time of birth.
Why Ultrasound is the Preferred Diagnostic Tool
Ultrasound, specifically Doppler ultrasonography, has become the preferred first-line imaging modality for evaluating soft tissue masses suspected to be hemangiomas. The procedure is non-invasive, does not expose the infant to ionizing radiation, and is significantly more cost-effective and portable than other imaging methods. Its ability to provide real-time images allows the clinician to assess the mass in different planes and observe its relationship to surrounding structures instantly.
The crucial advantage of ultrasound is its capacity to evaluate blood flow within the lesion using the Doppler technique. This feature helps distinguish a fast-flow hemangioma from a slow-flow vascular malformation, which is necessary for accurate diagnosis and treatment planning. While magnetic resonance imaging (MRI) may be used for very large or deep lesions involving sensitive structures, ultrasound is generally sufficient for initial diagnosis and subsequent size monitoring.
Interpreting the Ultrasound Findings
When viewing a hemangioma on a standard ultrasound, the lesion most commonly appears brighter than the surrounding tissue, a characteristic known as being hyperechoic. The tumor often has a well-defined shape and a somewhat lobulated or “bumpy” internal structure, particularly during the rapid growth phase. However, the echogenicity can vary; a lesion may appear isoechoic (the same brightness as surrounding tissue) or even hypoechoic (darker) in some cases.
The most definitive information comes from the color Doppler analysis, which highlights the movement of blood within the mass. Proliferating infantile hemangiomas are typically characterized by high-velocity blood flow and a low-resistance arterial waveform, reflecting the rapid growth and high metabolic demand of the tumor cells. This pattern helps differentiate it from a low-flow vascular malformation, which exhibits minimal or slow flow.
The ultrasound also allows for precise measurement of the lesion’s maximum dimensions, including its depth beneath the skin surface. This sizing is critical, as it establishes a baseline for monitoring the tumor’s growth or regression over time. Detecting specific features, such as prominent feeding vessels or deep extension into muscle or fat, helps the medical team assess the potential for complications.
Post-Diagnosis Management and Monitoring
Following a confirmed hemangioma diagnosis via ultrasound, the management strategy for most low-risk lesions is observation, often referred to as “watchful waiting.” This approach is appropriate because the majority of infantile hemangiomas will spontaneously involute without causing functional issues or permanent disfigurement. Low-risk lesions are generally small, localized, and not located near sensitive areas like the eyes or airway.
Periodic follow-up ultrasounds are often scheduled, particularly during the first year of life, to track changes in size and blood flow characteristics. Intervention becomes necessary if the lesion is causing functional impairment, such as blocking vision or the airway, or if complications like ulceration or rapid, aggressive growth occur.