Hemangioma: Definition and Classification
A hemangioma is a benign vascular tumor characterized by abnormal proliferation of endothelial cells and aberrant blood vessel architecture, with infantile hemangiomas being the most common benign neoplasm of infancy, occurring in 4-5% of infants. 1
Types of Hemangiomas
Infantile Hemangiomas (IHs)
- True neoplasms with increased mitotic activity and endothelial cell turnover 1
- Distinct from vascular malformations which are abnormalities of embryonic development 1
- Become clinically evident within first few weeks of life
- Progress through phases of latency, growth, and plateau by first year of life
- Complete or partial involution by 4 years in 90% of cases (may continue to 8 years) 1
Classification by Soft-Tissue Depth 1
- Superficial: Red with little/no subcutaneous component (formerly "strawberry" hemangiomas)
- Deep: Blue and located below skin surface (formerly "cavernous" hemangiomas)
- Combined (mixed): Both superficial and deep components present
Classification by Anatomic Appearance 1
- Localized: Well-defined focal lesions (appearing from central point)
- Segmental: Involving an anatomic region, often plaque-like, >5 cm in diameter
- Indeterminate: Neither clearly localized nor segmental
- Multifocal: Multiple discrete hemangiomas at different sites
Clinical Characteristics
Risk Factors for Infantile Hemangiomas 1
- Prematurity
- White race (3-10%)
- Female sex (female:male ratio 1.4:1 to 3:1)
Natural History
- Most infantile hemangiomas are diagnosed clinically 1
- Typical growth pattern: rapid proliferation followed by gradual involution 1
- Immunohistochemically stain positive for erythrocyte-type glucose transporter protein 1
Locations
- Can occur in any organ of the human body 2
- Common locations include skin, soft tissues, liver, and rarely airway
- Airway hemangiomas most commonly localized in subglottic airway 1
Diagnostic Considerations
When Imaging Is Indicated 1
- Superficial lesions with atypical features
- Deep lesions difficult to assess physically
- Central or segmental location in face/ears, breast, midline lumbosacral region
- Lesions ≥4 cm
- Presence of ≥5 hemangiomas
- Rapid growth rate
Imaging Characteristics
- MRI: Preferred modality for detailed evaluation 3
- Liver hemangiomas: Typically hyperintense on T2-weighted MRI with centripetal filling pattern after contrast 2
- CEUS (Contrast Enhanced Ultrasound): For liver hemangiomas - peripheral nodular enhancement (74%) in arterial phase and complete (78%) or incomplete (22%) centripetal filling in portal venous and late phases 1
Associated Conditions
PHACE Syndrome 1
- Posterior fossa malformations
- Hemangioma
- Arterial anomalies
- Coarctation of aorta/cardiac defects
- Eye abnormalities
Kasabach-Merritt Phenomenon (KMP) 3
- Important distinction: KMP occurs exclusively with kaposiform hemangioendothelioma or tufted angioma, NOT with common infantile hemangiomas
- Characterized by life-threatening consumptive coagulopathy with profound thrombocytopenia and hypofibrinogenemia
Management Considerations
Treatment Indications
- Most hemangiomas are small, nonproblematic, and can be managed conservatively 4
- Treatment indicated for symptomatic lesions with:
- Ulceration
- Bleeding
- Vision disturbances
- Functional limitations
- Disfigurement
Treatment Options for Infantile Hemangiomas 1, 3
- First-line: Propranolol (1-3 mg/kg/day divided into 2-3 doses)
- Alternative: Oral corticosteroids (prednisolone/prednisone 2-3 mg/kg/day)
- Topical: Timolol for thin/superficial IHs
- Procedural: Laser therapy for early lesions, focal lesions, or residual telangiectasias
- Surgical: Most useful for treatment of residual skin changes after involution
Liver Hemangiomas 5
- Most common benign liver tumors
- Observation justified for asymptomatic giant liver hemangiomas (>5 cm)
- Surgical resection indicated for:
- Abdominal (mechanical) complaints
- Complications
- Inconclusive diagnosis
- Enucleation is the preferred surgical method
Special Considerations
Pregnancy 1
- Hemangiomas can increase in size during pregnancy
- Most pregnancies with hemangiomas do not develop complications
- Risk of hepatic rupture in giant (>4 cm) liver hemangioma is 3.2%
- Risk increases to 5% in lesions >10 cm
- Close monitoring recommended during pregnancy
Common Pitfalls
- Historical terms like "cavernous hemangioma" and "venous hemangioma" have contributed to diagnostic confusion 3
- Atypical features in high-flow hemangiomas can be mistaken for hepatocellular carcinomas or focal nodular hyperplasia 1
- Important to differentiate hemangiomas from other vascular anomalies as management approaches differ significantly 3