Hepatic hemangioma overview

# Overview
Hepatic hemangioma is a noncancerous liver tumor made of dilated (widened) blood vessels. It is the most common primary liver tumor. The first case of spontaneous rupture of a hepatic hemangioma was described by Van Haefen in 1898. Hepatic hemangioma may be classified into typical and atypical hemangioma. Development of hepatic hemangioma is the result of genetic mutations, overexpression of angiogenic fators and downregulation of inhibitors of angiogenesis. Hepatic hemangioma may be associated with Kasabach-Merritt syndrome, hereditary hemorrhagic telangiectasia, hepatic arterio-portal shunts, extra hepatic hemangiomata, hemolytic anemia, focal nodular hyperplasia. On gross pathology, a well-circumscribed subcapsular tumor may be suggestive of hepatic hemangioma. Hepatic hemangioma must be differentiated from other diseases such as hepatic abscess, hepatocellular carcinoma, hepatic cyst, and hemangioendothelioma. The prevalence of hepatic hemangioma is estimated to be up to 20% in general population. Hepatic hemangioma commonly affects individuals between 30 to 50 years of age. If left untreated, patients with giant hepatic hemangiomas may progress to develop complications. Complications of hepatic hemangioma include spontaneous rupture, acute hemorrhagic shock, and upper abdominal pain. Prognosis is generally excellent, and the mortality rate of patients with spontaneous rupture of hepatic hemangioma is approximately 30-40%. Symptoms of hepatic hemangioma include intermittent right upper quadrant abdominal pain, dyspepsia, early satiety, and vomiting. Common physical examination findings of hepatic hemangioma include palpable upper abdominal mass, hepatomegaly, and biliary colic. Some patients with hepatic hemangioma may have elevated concentration of transaminases, bilirubin, and alkaline phosphatase even in asymptomatic cases. On CT scan, hepatic hemangioma is characterized by dynamic enhancement pattern related to the size of its vascular space. Observation is recommended for patients with small hemangiomas (less than 4 cm), whereas asymptomatic patients are followed up with periodic radiological examination. Elective surgical resection is recommended among all symptomatic patients with large hepatic hemangioma > 5 cm.

# Historical Perspective
The first case of spontaneous rupture of a hepatic hemangioma was described by Van Haefen in 1898.

# Classification
Hepatic hemangioma may be classified into typical and atypical hemangioma.

# Pathophysiology
Development of hepatic hemangioma is the result of genetic mutations, overexpression of angiogenic fators and downregulation of inhibitors of angiogenesis. Hepatic hemangioma may be associated with Kasabach-Merritt syndrome, hereditary hemorrhagic telangiectasia, hepatic arterio-portal shunts, extra hepatic hemangiomata, hemolytic anemia, focal nodular hyperplasia. On gross pathology, a well-circumscribed, subcapsular tumor may be suggestive of hepatic hemangioma. On microscopic histopathological analysis channels lined by benign endothelium containing RBCs, surrounding (non-endothelial) cells without significant atypia are findings of hepatic hemangioma.

# Causes
There are no established causes for hepatic hemangioma.

# Differentiating Hepatic hemangioma from other Diseases
Hepatic hemangioma must be differentiated from other diseases such as hepatic abscess, hepatocellular carcinoma, hepatic cyst, and hemangioendothelioma.

# Epidemiology and Demographics
The prevalence of hepatic hemangioma is estimated to be up to 20% in general population. Hepatic hemangioma commonly affects individuals between 30 to 50 years of age. Females are more commonly affected with hepatic hemangioma than males. The female to male ratio is 3:1.

# Risk Factors
Common risk factors in the development of hepatic hemangioma are age, female gender, oral contraceptive pills, and pregnancy.

# Screening
According to the American Association for the Study of Liver Diseases and United States Preventive Services Task Force, there is insufficient evidence to recommend routine screening for hepatic hemangioma.

# Natural History, Complications and Prognosis
If left untreated, patients with giant hepatic hemangiomas may progress to develop complications. Complications of hepatic hemangioma include spontaneous rupture, acute hemorrhagic shock, and upper abdominal pain.
Prognosis is generally excellent, and the mortality rate of patients with spontaneous rupture of hepatic hemangioma is approximately 30-40%.

# Diagnosis

## History and symptoms
Symptoms of hepatic hemangioma include intermittent right upper quadrant abdominal pain, dyspepsia, early satiety, and vomiting.

## Physical Examination
Common physical examination findings of hepatic hemangioma include palpable upper abdominal mass, hepatomegaly, and biliary colic.

## Laboratory Findings
Some patients with hepatic hemangioma may have elevated concentration of transaminases, bilirubin, and alkaline phosphatase even in asymptomatic cases.

## CT
On CT scan, hepatic hemangioma is characterized by dynamic enhancement pattern related to the size of its vascular space.

## MRI
On MRI, hepatic hemangioma is characterized by hypointensity on T1-weighted imaging and hyperintensity on T2-weighted imaging.

## Ultrasound
On liver ultrasound, hepatic hemangioma is characterized by well-defined hyperechoic lesions.

## Other Imaging Findings
Other imaging finding for hepatic hemangioma include SPECT, which demonstrates decreased activity on initial dynamic images and increased activity on delayed, blood pool images.

## Other Diagnostic Studies
Other diagnostic studies for hepatic hemangioma include biopsy, which should be avoided due to risk of bleeding.

# Treatment

## Medical therapy
Observation is recommended for patients with small hemangiomas (less than 4 cm), whereas asymptomatic patients are followed up with periodic radiological examination.

## Surgery
Elective surgical resection is recommended among symptomatic patients with large hepatic hemangioma > 5 cm.

## Prevention
There are no primary or secondary preventive measures available for hepatic hemangioma.