Liver hemangioma

Overview

Liver hemangioma

Hemangiomas are benign vascular tumors that can affect the skin or the viscera. Congenital hemangioma (CH) is fully developed at birth and involutes in early infancy, whereas infantile hemangioma (IH) develops fast after birth and involutes slowly. Patients with hepatic hemangiomas may be clinically quiet and only discovered as an incidental abnormality on ultrasonography.

What is liver hemangioma?

liver hemangioma definition

Hemangiomas are innocuous vascular tumors of infancy that can affect the skin or the viscera, including the liver. Understanding these lesions has progressed quickly in recent years, reconciling formerly vast variations in nomenclature and description. They are remarkable for their disparate clinical outcomes.

Congenital hemangioma (CH) is fully developed at birth and then involutes in early infancy, whereas infantile hemangioma (IH) develops fast after birth and then involutes slowly. Infantile hepatic hemangioma (IHH) may be further described by its pattern of involvement, whether localized, multifocal, or diffuse.

Typical hemangiomas, also known as capillary hemangiomas, ranging in size from a few millimeters to 3 cm, do not grow in size over time, and hence are unlikely to cause future symptoms. Small (mm-3 cm) and medium (3 cm-10 cm) hemangiomas are well-defined lesions that require no active treatment other than routine check-ups.

However, so-called large hepatic hemangiomas of up to 10 cm (most typically) and even 20+ cm in size can and generally do develop symptoms and problems that necessitate immediate surgical intervention or other type of therapy.

Epidemiology

Infantile hemangiomas are the most frequent kind of vascular tumor in infancy, affecting 4 to 5% of term newborns, with a female and white predominance. Similarly, IHH is the most prevalent infantile hepatic tumor. Low birth weight, preterm, and a positive family history are all risk factors. CH, on the other hand, is uncommon. The exact incidence is unknown, however it is believed to affect fewer than 1% of all neonates. In one case series, CH accounted for only 14 percent of all infancy vascular tumors. In the literature, there are no recognized risk factors for CH.

Etiology

Infantile hemangiomas are vascular tumors that appear in infancy but differ in their underlying origin and clinical outcome. In both cases, the underlying pathogenesis is only partially understood. In the case of IH, lesions are thought to occur as a result of vasculogenesis and angiogenesis dysregulation. Hypoxic stress appears to be a triggering signal, causing VEG-F and other angiogenic factors to over-express, resulting in aberrant fetal endothelial cell proliferation.

Somatic activating mutations are thought to have a role in the pathogenesis of CH. Recent research has shown mutations in the alleles GNAQ and GNA11 in CH. Interestingly, both RICH and NICH have comparable mutations, suggesting that their disparities in clinical behavior may be due to postnatal circumstances or epigenetics.

Adulthood, chronic medication use (such as steroid use, can hasten the development of an existing HH), female sex: estrogen therapy, use of oral contraceptives (increase the risk or increase the size, discontinuing contraceptive regimen can lead to lesion regression, but not always); pregnancy and multiparity (by disrupting estrogen and progesterone hormone levels, leading to an increase in the size of a preexisting HH); Genetic gene penetrance or sex hormone proliferative factors could also play a role.

Pathophysiology

Liver Hemangioma Pathophysiology

There are three main types of involvement in infantile hepatic hemangioma: localized, multifocal, and diffuse. Focal IHH is a single hepatic lesion that is usually asymptomatic and is only seldom linked with cutaneous IH.

Multifocal IHH is made up of numerous separate lesions in the liver, which are classified differently in the literature as at least five or up to 10 lesions. They are also frequently asymptomatic, despite the fact that arteriovenous or portovenous shunting is more likely to develop high output heart failure.

Diffuse IHH, also known as diffuse newborn hemangiomatosis, is distinguished by severe liver involvement and near total displacement of the liver parenchyma.

These youngsters are far more likely to seek medical help for difficulties. For starters, large hepatomegaly can compress neighboring local tissues such as the thoracic cavity, inferior cava, and abdominal contents.

This can result in abdominal compartment syndrome, respiratory failure, and, in the end, multisystem organ failure. Diffuse IHH can also cause an overproduction of type III iodothyronine deiodinase, which deactivates thyroxine, resulting in severe hypothyroidism. Due to insufficient contractility, this might result in substantial developmental delay and heart failure. High output cardiac failure has been documented as a result of the lesion's extremely vascular character.

CH can exhibit three unique patterns. Tumors may rapidly involute in infancy and thus be referred to as rapidly involuting congenital hemangioma , do not involute and thus be referred to as non-involuting congenital hemangioma, or partially involute and thus be referred to as partially involuting congenital hemangioma.

CH might be asymptomatic can be detected via standard screening. When they become symptomatic, they can produce temporary thrombocytopenia and coagulopathy, which is separate from the Kasabach-Merritt phenomenon, which is an aggressive and potentially fatal condition that is only linked with kaposiform hemangioendothelioma and tufted angioma.

Other uncommon consequences include disseminated intravascular coagulation, hepatic failure caused by liver parenchyma displacement, and high output cardiac failure caused by arteriovenous and portovenous shunting.

Symptoms

Liver Hemangioma Symptoms

Both IHH and hepatic CH can be clinically asymptomatic and only discovered on ultrasonography for other reasons, such as standard prenatal ultrasound. On physical examination, they may be recognized as hepatomegaly if they are of large size.

The majority of lesions are asymptomatic at the time of presentation. As described in the pathophysiology section, presenting characteristics may include high output cardiac failure, hypothyroidism, or compression of local tissues if symptomatic. A minor transitory coagulopathy may result in a petechial rash in the case of CH.

The most frequent complaint is pain in the right upper hemiabdomen; others include decreased appetite, premature satiation sensation, nausea, vomiting, abdominal discomfort: feeling full, postprandial bloating, early or late. These symptoms may suggest the existence of a hemangioma or may be caused by other illnesses that are unrelated to the presence of HH.

Physical exam can detect hepatomegaly and very rarely a palpable mass. HH show complications depending on size and location:

Inflammatory, acute (fever) and chronic
Mechanical: rupture, spontaneous or traumatic: intra-abdominal mass disruption trauma, or marginal trauma when located in the proximity of the costal margin
Bleeding: intratumoral or intraperitoneal, with or without consumptive coagulopathy.

Diagnosis

Liver Hemangioma Diagnosis

Clinical evidence can be used to make a diagnosis of cutaneous IH and CH. Hepatic lesions, on the other hand, may not be properly evaluated with a physical exam alone. Biopsy and subsequent histological analysis can be used to provide a definitive diagnosis of IH and CH; however, this is typically challenging since lesions are very vascular and pose a bleeding risk. As a result, the clinical history, traditional radiographic features, and laboratory testing to rule out malignant processes can all be employed to determine the diagnosis.

The clinical course of IH and CH may be used to make a diagnosis. Serial ultrasounds should be performed on both lesions. A lesion that develops fast from birth until approximately eight months of age and then begins to recede is consistent with IH, whereas a lesion that is completely formed at birth and gradually regresses is compatible with CH.

Distinctive imaging findings may aid in the diagnosis of either CH or IH. In the case of CH, the lesion on US, CT, or MRI may seem remarkably heterogeneous, with a peripheral ring of contrast enhancement and low center enhancement. IH may have comparable characteristics. Calcifications, which are common in CH but not in IH, may be a differentiating characteristic between the two.

Documentation of a declining serum AFP and negative urine catecholamines may be useful in ruling out hepatoblastoma or neuroblastoma in both circumstances.

Liver hemangioma ultrasound

Ultrasound is frequently the initial diagnostic procedure for HH because of its wide availability, absence of irradiation, and repeatability. The fundamental drawback of US is that it is largely dependent on the operator and the patient. HH presents as a hyperechoic homogeneous nodule with well-defined borders and posterior acoustic enhancement on conventional ultrasonography. Furthermore, HH normally does not vary in size during follow-up tests or when comparing the current scan to prior ones.

The histology of the HH explains the hyperechoic pattern on US - the hyperechogenicity is caused by the multiple contacts between the endothelial lined sinuses that comprise the HH and the blood within them. Small HH typically have a hyperechoic appearance; larger lesions, due to possible necrosis, hemorrhage, or fibrosis, may appear inhomogeneous, with mixed echogenicity (hypo- and hyperechoic). Atypical HH refers to lesions with such echo patterns. Most HH have little or no Doppler signal on Doppler US.

However, not all hyperechoic masses should be classified as HH. This echo pattern is also found in benign (adenomas) and malignant disease (hepatocellular carcinoma, metastasis). As previously stated, steady results on serial tests are a fairly reliable marker of benign illness in clinical practice. The US has a high degree of accuracy in distinguishing HH from malignant hyperechoic tumors.

The lack of lesion blood flow in HH on Doppler US is also a reliable indicator for hepatocellular carcinoma (HCC), which usually includes intra- or peritumoral vascularity. A peripheral echogenic ring in hypoechoic lesions might indicate HH. A peripheral perilesional hypoechoic rim, termed as the "target sign," on the other hand, is uncommon in HH.

Another possibility is focal nodular hyperplasia (FNH), which is recognized by the "spoke-wheel sign." Keep in mind that a typical hemangioma may seem hypoechoic in comparison to the extremely hyperechoic liver parenchyma while studying the fatty liver.

On CT scans, the typical HH presents as a hypodense, well-defined lesion with peripheral nodular enhancement and increasing centripetal homogenous filling following contrast injection. This pattern cannot be seen in extremely small lesions smaller than 5 mm in size, which might be difficult to describe. Atypical HH, like CEUS, might have distinct enhancing patterns on CT.

Non-enhancing intralesional patches might coexist with fibrosis, thrombosis, or necrosis, resulting in a variable appearance. In the arterial phase, HH that are homogeneous and quickly enhancing might be misinterpreted for hypervascular tumors. HH might seem hyperdense compared to the neighboring liver parenchyma in patients with significant fatty infiltration of the liver. The primary drawbacks of CT include radiation and the use of iodine contrast medium.

On MRI,

The "cotton-wool" aspect is characterized by a well-demarcated, homogeneous lesion that is hypointense on T1-weighted images and hyperintense on T2-weighted imaging.

Diffusion-weighted images can also help distinguish HH from malignant lesions. In MRI, UCA is gadolinium-based and can be utilized in individuals with iodinated contrast agent allergies or renal impairment, for whom CT is contraindicated.

Management

Liver Hemangioma Management

Both IH and CH treatment is supportive and tries to address any consequences, as both lesions usually cure on their own. In situations when difficulties exist, treatment is advised.

Corticosteroids have always been the therapy of choice for IH. Oral propranolol has been the therapy of choice for cutaneous IH that causes deformity or interferes with eyesight. The specific mechanism is unknown, however it is thought to modulate the VEGF pathway, which is involved in the formation of the lesion. Propranolol has also been demonstrated to be useful in the treatment of IHH.

IHH surgical resection and embolization are reserved for serious consequences such as high output heart failure, abdominal compartment syndrome, and respiratory failure. Surgical resection complications include bleeding, whereas embolization can result in liver necrosis, cirrhosis, and sepsis. Thyroid replacement will be required for infants with diffuse IHH and hypothyroidism.

There is no medicinal therapy that has been shown to cause regression of congenital hemangioma. Corticosteroids had previously been tried and failed. In the case of active bleeding or serious heart failure, surgical resection or embolization may be needed.

Serial ultrasounds should be conducted in both situations to document regression. IH develops fast in infancy, normally achieves peak size by nine months, and is projected to regress by 80% by age four, whereas RICH is expected to regress entirely by 12 to 14 months.

Rapid development in size, discomfort despite analgesics, or both are indications for surgery. Dimensions, localization, or danger of intratumoral thrombosis, rupture, or other consequences are now regarded absolute reasons for surgery.

Aside from surgery, other therapies for symptomatic HH include artery embolization and radiofrequency ablation. Segmental resections, lobectomy, or enucleation of the hemangioma can be performed either open surgery or laparoscopy.

Surgical resection:

For elective surgery, the decision is influenced not just by size and location, but also by the surgeon's preference and technical expertise. Increasingly, operations are being performed in a less invasive manner - laparoscopically and, more recently, with robotic surgery assisting the technical abilities. Postoperative morbidity is modest for all procedures, and HH seldom recurs after surgery. Large tumors that fill the whole lobe may necessitate a right or left hepatectomy. According to the literature, emergency operations have a high death rate.

Selective or supra-selective angiographic embolization with polyvinyl alcohol or other compounds via hepatic artery catheterization can result in tumor decrease. Only hemangiomas with a clearly identifiable arterial blood supply are successful in controlling and reversing tumor development.
The long-term success rate of arterial embolization has not been thoroughly examined. Prior to resection, portal vein embolization (PVE) is now commonly utilized to enhance the remaining (post-surgical) viable liver parenchyma, offering more favorable circumstances for elective major surgery and reducing the risk of complications.
Selective transhepatic closure of the HH main feeding arteries can successfully minimize intratumoral shunt, which would otherwise result in congestive heart failure.
In modest trials, radiofrequency ablation performed laparoscopically or percutaneously under ultrasound control has been used to control pain.
Irradiation of the liver
For extensive or diffuse bilateral lesions, orthotopic liver transplantation is required. There have only been a few examples described in the literature.

Differential Diagnosis

A hepatic hemangioma can be differentiated from metastatic or atypical neuroblastoma, hepatoblastoma, mesenchymal hamartoma, kaposiform hemangioendothelioma, embryonal sarcoma, or angiosarcoma. Given the malignant potential of many of these lesions, it is vital to conduct a thorough examination and serial surveillance of the lesion.

Conclusion

Liver hemangioma

Hepatic hemangiomas are benign vascular tumors of infancy that involve the liver. There are two types: infantile hepatic hemangioma (IHH) and congenital hemangioma.

While the majority of persons with HH have no signs or symptoms, and the majority of HH are non-progressive and do not require treatment, there are a tiny number of instances with fast volumetric development or problems that necessitate adequate care. To present, the outcomes of clinical and analytical tests, particularly for imaging methods, have shown that for minor HH, routine follow-up is sufficient.

The progression of cavernous HH is unexpected and frequently unpleasant, with major consequences necessitating specialized surgical competence in tough situations. Hepatic hemangiomas must be distinguished from other localized hepatic lesions; co-occurring disorders are also conceivable.

Types are normally diagnosed based on their clinical history, however it is crucial to remember that both lesions are expected to disappear with time. Both lesions need close monitoring with successive ultrasounds and, in general, do not necessitate particular intervention, instead requiring just supportive therapy focused on the consequences.

An interprofessional team comprised of a pediatrician or nurse practitioner, a pediatric hematologist/oncologist, serial imaging, and careful surveillance for complications should closely monitor these lesions.