Hepatic hemangioma (HH) is the most common benign liver tumor. It consists of blood-filled cavities fed by the hepatic arterial circulation, with walls lined by a single layer of endothelial cells, a veritable chaotic entanglement of distorted blood vessels confined to a region as small as a few mm and as large as 10 cm, 20 cm and even 40 cm. The frequency is higher among adults, with a prevalent age at the initial diagnostic in the range of 30-50 years. Literature places the HH incidence at 0.4% to 20% of the total population. At necropsy, the frequency is of 0.4 to 7.3%, all the authors agreeing with an incidence of over 7%. The HH prevalence in the general population varies greatly, most often being discovered incidentally during imaging investigations for various unrelated pathologies. Regarding sex distribution, it seems that women are more susceptible, as confirmed by all pertaining studies, with a reported 4.5:1 to 5:1 ratio of female to male cases. Most often, HH are mono-lesions but multiple-lesions are possible; they account for 2.3% and up to 20-30% of the cases, depending on the source. At the initial diagnosis, the majority of HH measure below 3 cm in size, the so-called capillary hemangiomas; of these, only 10% undergo a size increase with time, for reasons still unknown. The next size class covers lesions between 3 cm and 10 cm in size, referred to as medium hemangiomas. Lastly, giant or cavernous hemangiomas measure up to 10 cm, with occasional literature reports of giant HH reaching 20-40+ cm in size. Location-wise they are most often found in the right liver lobe, often in segment IV, often marginal.
Operative intervention for liver hemangiomas remains a controversial topic. Previous studies from major hepatobiliary centres have proposed varying indications for a hemangioma resection. Findings from the present study demonstrate that operative management of symptomatic hemangiomas remains an effective therapy and can be performed with low morbidity to the patient. However, aside from abdominal symptoms, prophylactic resections in the setting of hemangioma enlargement, size, or patient anxiety is not advised as the risk of developing life-threatening associated complications is rare.
Established Complications. In the minority of cases that present as a surgical emergency due to haemorrhage, rupture, thrombosis and infarction, surgical management may be the only appropriate course of action. There is also a role for the elective surgical management of giant haemangiomata, albeit in a highly selected group of patients. As demonstrated by the data presented above, an operative approach with the objective of preventing future complications of giant haemangiomata is less easy to justify.
Diagnostic Uncertainty. Despite improvements in non-invasive imaging technology, cases of diagnostic uncertainty continue to pose a challenge. In situations where it is not possible to exclude malignancy, surgical intervention by formal liver resection may be indicated. In almost all situations, the use of percutaneous liver biopsy for the differentiation of giant haemangiomata from malignant liver lesions cannot be justified. The risks of haemorrhage as a result of biopsying a giant haemangioma are appreciable and, together with the risks of needle track seeding and intra-abdominal dissemination of a potentially curable malignancy, mean that biopsy in this setting must be avoided.
Incapacitating Symptoms. Having taken all possible steps to ensure that symptoms are attributable to the haemangioma, surgical resection may be justified on grounds of intractable symptoms. Patients with clearly defined abdominal compressive symptoms may be more likely to derive benefit from surgery than patients with non-specific abdominal discomfort, although this is not backed up by a meaningful body of evidence. Management of this group of patients is, by necessity, highly individualised. Despite apparently satisfactory surgical management, symptoms persist in approximately 25% of patients following resection of seemingly symptomatic haemangiomata.
While most people with HH show no sign or symptom, and most HH are non-progressing and do not require treatment, there is a small number of cases with rapid volumetric growth or complications, which prompt for appropriate therapy. The results of clinical and laboratory investigations to date, mostly for imaging techniques, have demonstrated that for small HH, regular follow-up is enough. For cavernous HH, the evolution is unpredictable and often unfavorable, with serious complications requiring particular surgical expertise in difficult cases. Hepatic hemangiomas require a careful diagnosis to differentiate from other focal hepatic lesions, co-occurring diagnoses are also possible.