Liver hemangiomas are one of the most common findings of the liver on CT. They are the most common benign tumor of the liver made up of blood vessels. Usually these are discovered on CTs done for different reasons and rarely cause problems, symptoms or need treatment. They can grow slowly, particularly in pregnant patients, and at times cause symptoms of pain in the right upper abdomen.
Classic liver hemangiomas have a typical appearance on CT. They have peripheral discontinuous contrast enhancement with progressive fill in. This means that the dye injected into your vein during CT goes to the the periphery of the tumor and causes small nodular bright areas which increase over time and eventually fill in completely over time. They change very little over serial follow up exams.
Hemangiomas are often imaged on single phase CTs done for different reasons. This means that we only get one look at the tumor on CT after the dye is given through your vein. This can lead to uncertainty over the diagnosis as the lesion is not completely characterized. The radiologist may then recommend another specialized CT or MR that allows looking at the tumor over multiple instances in time. This will allow a confident diagnosis in many cases.
While the classic appearance of hemangioma allows a confident diagnosis, there are many unusual appearances. Some of these can even overlap with cancers of the liver. One of the more common variants is called a flash filling hemangioma. These fill with contrast immediately and completely, often retaining the contrast over time. In other words, the tumor appears bright to liver over time.
Other variants include enhancement patterns that are not typical or mimic other tumors. Some hemangiomas can be calficied or pedunculated meaning they protrude from the liver. Some of these hemangiomas can be multiple or huge in size. Some giant hemangiomas can be greater then 10 cm in size. These hemangiomas can bleed, push on structures and cause symptoms in some cases.
Hepatic hemangiomas can also look like more concerning lesions. Metastasis or spread of cancer to the liver can look like hemangioma when they are hypervascular or take up contrast early. They can even fill with contrast over time. Usually, you won’t see the discontinuous enhancement along the periphery but more of a ring. Hepatic carcinoma is a cancer of the liver which classically enhances with contrast early and washes out later. This means that it’s bright to liver initially and then becomes darker later unlike a hemangioma.
Hemangiomas are therefore very common, rarely symptomatic, and discovered on imaging incidentally in most cases. That is, they are found when the CT is being done for other reasons. They are benign and usually require no treatment, They can be diagnosed confidently in many cases and left alone. Confusing or uncertain cases can further be evaluated with MRI or followed in 6 months or so with another scan.