Hepatic hemangiomas, are benign tumors of the liver. Hepatic cavernous hemangiomas are the most common. Spongiform hemangiomas are usually solitary and occur mostly in the right lobe of the liver; about 10% are multiple and may be distributed in one or both lobes of the liver. Hemangiomas present in the liver as dark red, bluish-purple cystic elevations. They are lobulated or nodular, soft, compressible, and mostly clearly demarcated from adjacent tissues. Patients are usually asymptomatic.
Mechanism of occurrence
The syndrome is more common in middle-aged women, with the incidence in women being six times higher than in men. Because this disease has no obvious symptoms and only presents as an intrahepatic occupying lesion, clinical attention should be paid to differentiate it from hepatocellular carcinoma.
The pathogenesis of hepatic hemangioma is still unclear, and there are two different understandings.
The growth of hepatic hemangioma is due to the expansion of blood sinusoids under the action of blood flow, which has intact endothelial cells, abundant elastic fibers under them, fibroblasts and smooth muscle cells in the middle membrane layer, and abundant and widely distributed collagen fibers in the mesenchyme, resulting in unclear boundary between inner, middle and outer membrane layers and disorderly arrangement of elastic fibers.
Secondly, hepatic hemangioma is considered to be a true tumor, and its growth is due to the formation of new vascular tissue. Hormones have an important role in the formation of new vascular tissue, and it is speculated that steroids act on a part of the emblematic structure spongy vessels of the vessel wall, and the possible mechanism is that steroids such as prednisone inhibit the collagen biosynthesis of the vessel wall; on the other hand steroids have the effect of stimulating or promoting angiogenesis. It has been reported that sex hormones can promote the proliferation, migration and even the formation of capillary-like structures in the vascular endothelium.
Similarly, clinical studies have confirmed the association of female hormones with the growth of hepatic hemangiomas. A long-term follow-up survey showed that 12.7% of female patients with hepatic hemangioma had an increase in tumor size during the follow-up period, but only 6.3% had a significant increase, and 22.7% of those treated with hormones had an increase in hepatic hemangioma diameter twice as large as the control group. All of the above indicate that the growth and recurrence of hepatic hemangioma are closely related to sex hormones, exogenous such as oral contraceptive drugs and endogenous such as pregnancy, i.e. pregnancy or oral contraceptive pills can accelerate tumor growth or recur after cure.
It has also been reported that the positive rate of VEGF expression in hepatic hemangioma is as high as 78%, and the higher the expression of VEGF, the more vigorous the proliferation of vascular endothelial cells, thus hepatic hemangioma should be regarded as a neoplastic organism. However, the real mechanism of hormone in the occurrence and development of hepatic hemangioma is not yet understood, which needs to be studied in depth to provide theoretical basis for clinical drug treatment of hepatic hemangioma.
Disease classification
1.Cavernous hemangioma: The cut surface is honeycomb, full of blood, microscopic examination shows cystic sinusoid of different sizes, filled with red blood cells, and sometimes thrombosis. The thrombus in the fibrous septum and sinusoids can be seen as calcification or venous stone.
2.Sclerosing hemangioma, in which the lumen is closed and the fibrous septum shows more degenerative changes.
3.Vascular endothelial cell tumor, vascular endothelial cells proliferate actively and are prone to malignant changes.
4.Hepatic capillary hemangioma with narrow lumen and more fibrous septal tissue.
Clinical manifestations
1.Small hemangioma is asymptomatic, but larger hemangioma may have distension and pain in the liver.
2.Small hemangioma is asymptomatic, while larger hemangioma may have palpable mass in the right upper abdomen and large liver.
3.Large liver, mass and compression symptoms appear due to the enlargement of tumor, which are mostly asymptomatic in early stage. Diagnosis is mainly based on ultrasound, cT, nuclear scan and hepatic arteriography to confirm the diagnosis. Smaller hemangiomas with no symptoms do not need to be treated and can be observed dynamically, while partial hepatectomy can be chosen for those with compression symptoms. Most hemangiomas are solitary and less than 4 cm in diameter. Hepatic hemangiomas are often found incidentally during ultrasound examination, and their size and shape and number are not certain, and they are often congenital in nature.
If the hepatic hemangioma is stationary and does not develop, it is usually not life-threatening without any conscious symptoms. Hepatic hemangioma may contain fibrous tissue and mechanized thrombus, which may cause swelling of tumor and distension of liver peritoneum due to repeated thrombosis.
Complications of hepatic hemangioma
1.Rupture of hepatic hemangioma: It may cause acute abdomen or internal bleeding symptoms.
2. Thrombocytopenia and hypofibrinogenemia: A few patients often suffer from this condition due to impaired coagulation mechanism.
3.Liver enlargement: When hemangioma grows up, it will cause liver enlargement.
4.Hepatic cysts: About 10% of patients can be complicated by liver cysts.
Diagnosis based on
Imaging examination (such as ultrasound, CT and MRI) is the main way to diagnose hepatic hemangioma at present.
X-ray plain film examination has little significance. Only giant hepatic hemangioma will show elevation of right diaphragm and gas compression changes in digestive tract, and it is non-specific. The possibility of hepatic hemangioma will be considered when the tumor appears calcification.
1.B ultrasound.
It shows a well-defined hypoechoic occupancy with a less pronounced posterior echogenic enhancement effect. B-mode ultrasound can detect hepatic hemangiomas >2 cm in diameter. The typical presentation is a well-defined hypoechoic lesion with less pronounced posterior echogenic enhancement. However, most small hemangiomas are strongly echogenic, with a tumor diameter of 5 cm or more, and show mixed internal high and low echogenicity with irregular borders and different shapes, due to intra-tumor fibrous changes, thrombosis or necrosis. Sometimes hepatocellular carcinoma can also have similar images, so other imaging examinations are needed to differentiate them.
2.CT.
Under CT scan, hepatic hemangioma appears as round or ovoid low-density foci, which may be multiple or single. Most of them have uniform density and clear borders, and the density of hemangioma in fatty liver is higher. When the intra-tumor mechanization is more, it shows stellate or fissure-like hypodensity, and sometimes the intra-tumor may show indefinite calcification. CT-enhanced imaging is very helpful for the characterization of hepatic hemangioma, especially for the differentiation from hepatocellular carcinoma, which mostly shows oval hypodense shadow on plain scan images and no differentiation between the two in terms of cT value (P>0.05), so enhanced examination is essential.
According to the special changes of blood in hepatic hemangioma, “two fast and one slow” CT enhancement scan technique is necessary for the diagnosis of hepatic hemangioma. The cT enhancement of hepatic hemangioma is characterized as follows: early lesion edges show high-density enhancement in line with the abdominal aorta of the same layer; the enhanced area shows progressive centripetal expansion; delayed (>5min) scan shows isointense filling of the lesion, and after another 1h delay, the lesion returns to the low density of the flat scan. Some scholars refer to this sign as the characteristic contrast “fast in, slow out” performance of liver hemangioma.
In contrast, the cT enhancement of hepatocellular carcinoma shows the unique CT sign of “fast in and fast out”, that is, the whole lesion reaches a uniform or inhomogeneous high density in the early stage (arterial stage), and then rapidly decreases and approaches the density of the liver parenchyma with rising density. The contrast is then rapidly discharged and returns to the hypointense shadow on plain scan. Liver metastases, on the other hand, tend to occur in middle-aged and elderly patients with a history of primary disease.
At the early stage of CT enhancement. Its edges or the whole lesion appears to be significantly enhanced. However, in the hepatic portal phase, the contrast is basically discharged, and some of them may have the “bull’s eye” sign, and the lesion on delayed scan is hypointense and rarely appears to be filled with isointensity.
3.MRI.
MRI has special diagnostic significance for this disease and will not miss small lesions. Patients with a diameter of 5 cm can be considered for surgical resection.
However, the indications can be relaxed for lesions in specific areas (hilar, square, caudate lobe). In recent years, the surgical resection technique of hepatic hemangioma has been improved by applying the waterjet separator – waterjet – provided by ERBE, Germany. Compared with the traditional surgery, waterjet surgery is an improvement in blood loss, blood transfusion, operation time and postoperative hospitalization days, which is worth advocating.
Indications for treatment
The indications for treatment of hepatic hemangioma are controversial. In 1970, Adam referred to tumors >4 cm in diameter as giant hepatic hemangioma and used this as an indication for surgery. Some authors have suggested that if the diameter of hemangioma is >5 cm, surgery should be performed regardless of the presence of clear clinical symptoms, but the requirements for the size of hemangioma vary from 8 cm, >lO cm to the largest >15 cm. Some authors have cited the risk of rupture and bleeding of hepatic hemangioma as an important reason for surgical treatment.
In recent years, with further understanding of the natural growth pattern of hepatic hemangioma, the indications for treatment of hepatic hemangioma have changed, and the number of cases of conservative observation without treatment has gradually increased. We believe that tumor size and concern about rupture and bleeding are not criteria for the need for surgical treatment of hepatic hemangioma. Spontaneous rupture of hepatic hemangioma is rare, with only a few dozen cases reported worldwide to date, and the risk of liver surgery is much higher.
Surgical indications for hepatic hemangioma should be strictly controlled. Specifically, they include.
1. Very clear symptoms (excluding other diseases that may cause similar symptoms);
2, rupture of the tumor or large flow arteriovenous fistula and coagulation dysfunction (Kasabach-Merrit syndrome);
3, other liver tumors cannot be excluded;
4.Hemangioma body diameter >10cm. However, when the diameter of the tumor is 5 cm to 10 cm and the following conditions are combined, it is considered as a relative indication for surgery, and treatment should be considered when the patient’s study, work and life are seriously affected by the psychological stress caused by the presence of the disease.
(1) Adjacent to the first and second hepatic hilum;
(2) Tumor growth rate >2cm in diameter per year;
(3) Tumor protruding from the edge of the liver, especially below the rib cage;
(4) Combination of other surgical disorders such as gallbladder stones. For hemangiomas located in the central part of the liver or caudal lobe, surgical treatment may require the removal of large pieces of liver tissue, and the complications and mortality rates of surgery are still difficult to be accepted by patients. Therefore, we do not advocate aggressive surgery, but rather close follow-up and strict control of surgical indications.
Treatment methods
1.Surgical methods are.
(1) Hepatic hemangioma resection or lobectomy;
(2) hepatic artery ligation;
(3) intraoperative cryotherapy.
2.Non-surgical treatment.
(1)Radiation therapy;
(2) Hepatic arteriography and tumor artery embolization.
Principles of drug use
Generally, drug therapy is not used. For surgical treatment, antibiotics in addition to basic drugs are used to prevent wound infection.
Evaluation of curative effect
1.Cure: CT and color ultrasound show that the mass disappears, the symptoms disappear and the incision heals without complications.
2.Improved: CT and color ultrasound showed that the swelling became smaller and the symptoms were reduced.
3.Unhealed: no change, or further enlargement of the mass.
Hepatic hemangioma is a benign lesion, and there is still no curative drug for hepatic hemangioma, so if the hemangioma is <5cm, there is no need to seek medical help, and regular follow-up can be done. If the tumor is >5cm and there are self-conscious symptoms, the patient should go to the hospital and follow the medical advice.