Causes

It's not clear what causes a liver hemangioma to form. Doctors believe liver hemangiomas are present at birth (congenital).

A liver hemangioma usually occurs as a single abnormal collection of blood vessels that is less than about 1.5 inches (about 4 centimeters) wide. Occasionally liver hemangiomas can be larger or occur in multiples. Large hemangiomas can occur in young children, but this is rare.

In most people, a liver hemangioma will never grow and never cause any signs and symptoms. But in a small number of people, a liver hemangioma will grow to cause symptoms and require treatment. It's not clear why this happens.