Definition of Liver Hemangioma
A liver hemangioma is a benign vascular tumor consisting of clusters of blood-filled cavities lined by endothelial cells and fed by the hepatic artery, representing the most common benign liver tumor that is typically discovered incidentally during imaging studies. 1, 2
Pathophysiology and Classification
- Hemangiomas are considered developmental vascular malformations rather than true neoplasms, though the exact pathophysiology remains incompletely understood 2, 3
- The lesions consist of endothelial-lined vascular spaces filled with blood, supplied exclusively by arterial vessels from the hepatic artery 1, 2
- Cavernous hemangioma is the most frequent histologic type encountered in clinical practice 4
Size-Based Categories
- Small hemangiomas (millimeters to 3 cm): Typically capillary hemangiomas that appear uniformly echogenic on ultrasound, do not increase in size over time, and are unlikely to cause symptoms 1, 2
- Medium hemangiomas (3-5 cm): Mainly echogenic on imaging, well-defined lesions requiring no active treatment beyond observation 1, 2
- Large hemangiomas (5-10 cm): Show mixed echogenicity patterns and have increased risk of complications 1, 2
- Giant hemangiomas (>10 cm): Can reach up to 20+ cm in rare cases, usually develop symptoms requiring intervention, with rupture risk of approximately 5% 5, 2
Clinical Presentation
- The vast majority of hemangiomas are asymptomatic and discovered incidentally as hepatic "incidentalomas" during imaging for unrelated conditions 2, 3
- Less than half present with overt clinical symptoms, most commonly upper abdominal pain from distension of Glisson's capsule, particularly with larger lesions 2, 6
- Rare complications include Kasabach-Merritt syndrome (consumptive coagulopathy), rupture, or compression of adjacent structures 7, 3