Hepatic hamartoma

　　1. Etiology

　　Hepatic hamartomas have always been considered as tumors formed during the growth and development period, accompanying the growth of the hepatic portal structures, rather than as new tumors. Some pathologists believe that it is very likely that the abnormal development of primitive mesenchymal cells is the cause. This abnormal development is likely to occur in the late embryonic stage, when the liver forms lobular structures and connects with bile ducts. Stocker and others described that the cystic transformation of mesenchymal tissue is accompanied by fluid accumulation caused by obstruction, while the lymphatics and the bile ducts involved in them lead to the enlargement of the tumor. After that, the tumor spreads and grows along the portal tract structures, forming islands embedded in normal tissue. Stocker and others also pointed out that due to the lack of evidence of mesenchymal tissue mitotic activity, it is indicated that most proliferation and growth occur before or just after birth, but the enlargement of cysts into massive tumors occurs in children. However, more recent theories assume that these lesions are actually more active than simple growth. In this case, an abnormal blood supply perfuses other normal liver tissue. The tissue at the lesion site eventually becomes ischemic and reactive cystic. Observations have found that some hamartomas have central necrosis and are connected to normal tissue by a pedicle, which supports this theory.

　　2. Pathogenesis

　　In 1956, Edmondson discovered that lymphangiomas, hamartomas, biliary cell fibroadenomas, cavernous lymphangiomas, pseudocystic mesenchymal hamartomas, and cystic hamartomas share the same histological characteristics and are therefore unifiedly named as hepatic mesenchymal hamartomas. Hepatic hamartomas commonly occur in the right lobe, near the margin, and have a nodular surface with irregular convexities and concavities. The gross and microscopic features of typical hepatic mesenchymal hamartomas can be distinctly distinguished from other liver tumors. Pathologically, they can be divided into two major categories: solid and cystic. The solid type includes those originating from liver cells and stroma, accompanied by a large amount of fibrous tissue, blood vessels, fat, and mucus. The lesions are typically characterized by large, well-defined or encapsulated tumors, generally with a diameter of 8 to 10 cm. Although many tumors are multicystic, large solitary cysts are more common. The lesions often have a pedicle and there are reports of torsion. The cystic type includes vascular, lymphovascular, and biliary hamartomas, which may have an epithelial lining. The gross tissue section of the specimen can appear brownish gray or hard fish meat-like, filled with serous or mucinous fluid within the cyst, separated by loose and mucinous tissue. The tissue between the cysts is pale, edematous, or reddish-brown, resembling normal hepatic mesenchymal tissue, and the histopathological characteristics include a mixture of cysts, bile ducts, liver cells, and mesenchymal tissue formed in different proportions. However, there are also reports of non-cystic, solid hepatic mesenchymal hamartomas. The bile ducts are surrounded, elongated, and deformed by connective tissue, distributed in the mesenchymal tissue. The liver cells are normal (without immature cells similar to those in hepatocellular carcinoma), and blood vessels and lymphatic structures may appear in the mesenchymal tissue of the tumor.

　　Under the microscope, it varies according to the origin. Solid hamartomas are mainly characterized by the proliferation of liver cells, bile duct hamartomas are mainly characterized by the proliferation of bile ducts and fibrous collagen matrix, and interstitial hamartomas are mainly characterized by the proliferation of mesenchymal tissue. A large amount of connective tissue is arranged in a central star pattern, and liver cells are arranged irregularly without forming lobules. The bile duct epithelium and blood vessels have been fibrosed. Dehnet observed the tumor under an electron microscope and found that it is composed of loose mucinous cells, mainly mature stromal cells and scattered liver cells, bile duct cells. Angioid hamartomas are mainly characterized by the proliferation of blood vessels and fibrous connective tissue. Cystic hamartomas can be seen with cystic cavities of different sizes, some of which are lined with a single layer of flat mesothelial cells, and some are connective tissue fissures. There are a small amount of bile ducts and liver cell cords around the tumor. The boundary between the tumor and normal tissue is distinct.

　　There are few reports of torsion in this disease, but it is not accompanied by liver cirrhosis and has no malignant tendency.

　　1. Compression of the diaphragm by the mass upward can lead to respiratory distress, and in severe cases, it can cause respiratory distress or cardiac insufficiency.

　　2. The systemic manifestations may include anemia and weight loss.

　　There are very few reports on the complications of this disease. For patients who need surgery, under the principle of careful selection of surgical methods, trying to preserve normal lung tissue, and preventing excessive resection, it is also possible to prevent complications during and after surgery. However, if the tumor is large and compresses the great vessels and lung tissue, causing chest deformity, it may also cause complications such as pneumonia, atelectasis, and bronchiectasis, which may worsen or complicate the condition. Therefore, when malignant tumors cannot be ruled out by clinical and X-ray examination, surgery should be performed as soon as possible.

　　The clinical features are asymptomatic rapid growth of a mass, which is more common in infants and young children, mostly seen from April to 2 years old, usually onset before the age of 5, with a male-to-female ratio of 2:1. Adult onset is extremely rare, but there are also reports. There are no symptoms in the early stage, and some have abdominal masses at birth. As growth and development progress, the mass can grow rapidly. When the tumor gradually increases in size, a mass can be palpated in the upper right abdomen, which is hard, non-tender, and moves up and down with respiration. In the late stage, abdominal painless giant masses and the resulting compressive symptoms may appear, with gastrointestinal symptoms such as nausea, vomiting, abdominal distension, constipation, and other gastrointestinal compressive symptoms. Compression of the diaphragm by the mass upward can lead to respiratory distress, and in severe cases, it can cause respiratory distress or cardiac insufficiency. Occasionally, pedunculated masses may cause tumor torsion, necrosis, and systemic manifestations such as anemia and weight loss.

　　Physical examination shows that the patient's abdomen is extremely distended, with varicose veins on the abdominal wall, a large mass can be palpated, with hard texture, irregular shape, no tenderness, and does not move up and down with respiration. Liver enlargement.

　　This disease is a relatively rare benign tumor, mostly occurring in infants and young children. The clinical features are mainly asymptomatic rapid enlargement of abdominal masses, with no typical specific signs. If a large liver mass is found, and metastatic cancer is excluded, alpha-fetoprotein (-), the patient's general condition is good, and the possibility of benignity is high. This disease should be considered. In addition to clinical symptoms and signs, B-ultrasound, CT, and other methods are helpful for diagnosis, but they can usually only suggest liver space-occupying lesions. Definitive diagnosis is often difficult, and definitive diagnosis still relies on pathological examination.

　　Patients should pay attention to keeping their mood pleasant, avoid anger and violent emotions, eat more vegetables and fruits, maintain smooth defecation, eat moderately, and be satisfied with 7 or 8 points of fullness. Eat less beef, mutton, pork, and dog meat, avoid greasy, thick foods, strong alcohol, and spicy fried foods. It is recommended to eat light and nutritious foods. Patients with hamartoma should avoid overexertion during work and household activities, do not carry heavy objects, and avoid strenuous exercise to prevent increased intra-abdominal pressure and tumor rupture and hemorrhage. They can do long-distance walking and other low-intensity exercises regularly, and pay attention to observe the size of the tumor.

　　Liver function can be within the normal range, with a few AFP levels elevated, which decrease after tumor resection, the cause is unknown and difficult to explain. Alpha-fetoprotein is negative, and CA19-9 may be elevated.

　　X-ray, abdominal ultrasound, CT, and MRI are helpful for diagnosis.

　　1. Ultrasound examination:Abdominal ultrasound shows clear boundaries of liver anechoic cysts, which can be solitary or multiple. Cysts with multiple cavities (circular or elliptical) can be seen within the tumor, with thick walls and large, uncalcified shadowy masses.

　　2. CT examination:CT shows hypovascular masses, encapsulated cysts and parenchymal tissues, with lower density than the liver. Large areas of inhomogeneous low density in the liver can be seen, as well as multiple cystic liquid dark areas. Currently, CT is a fast and inexpensive method, and it can also well display anatomical boundaries to determine the possibility of surgical resection.

　　3. Angiography:Manifested as a mass with few or no blood vessels (small blood vessels between fibrous tissues), the invasion of the surrounding liver parenchyma or invasion of the inferior vena cava in the interlobular hamartoma of the liver is not common. Because the blood supply of the lesion is less, angiography plays a very small role in diagnosis and surgery.

　　4. Radionuclide scanning:It also helps in the diagnosis of the disease.

　　5. Abdominal flat film:The position of other normal intestinal gas images is lower, but calcification is not always detectable in the image.

　　6. MRI:It is also an effective means. With the development of advanced MRI technology such as gradient echo imaging and spin echo, MRI has been greatly improved.

　　Firstly, what foods are good for liver hamartoma patients

　　1. It is advisable to eat light, nutritious foods.

　　2. Eat more fungal foods, fresh vegetables, and fruits.

　　Secondly, what foods should not liver hamartoma patients eat

　　1. Avoid greasy, thick, strong alcohol, and fried food.

　　2. Avoid hard or spicy刺激性 food.

　　3. Avoid fish, shrimp, crab, beef, mutton, pork, and dog meat.

　　(The above information is for reference only, please consult a doctor for details)

　　1. Treatment

　　Surgical treatment is still the preferred method for this disease. Although the tumor is benign, its rapid growth increases the difficulty of surgery, so it is advisable to have surgery as soon as possible. According to the location of the tumor, tumor resection or lobectomy of the liver can be performed. Since hamartoma often has clear boundaries with normal liver tissue, tumor excision can be chosen. If the tumor is closely adherent to the liver tissue, partial liver resection or lobectomy can be performed. Children's liver tissue is often without sclerosis and has strong regeneration ability, providing conditions for complex extensive liver resection. For large tumors that are adherent to the first, second liver gates and inferior vena cava, the method should be selected according to the size, location, and relationship with surrounding blood vessels of the mass. If necessary, take full liver blood flow blockage or hypothermic perfusion full liver blood flow blockage resection of the liver, which lowers the local temperature of the liver, keeps the surgical field in a bloodless state, makes the anatomy clear, and protects liver cells, which is conducive to the recovery of liver function after surgery.

　　2. Prognosis

　　After long-term clinical examination, it has been confirmed that the traditionally considered benign lesion, mesenchymal hamartoma of the liver, is a developmental malformation without a tendency to malignancy. Although mesenchymal hamartoma of the liver may produce growth characteristics similar to neoplasms due to rapid expansion of cysts, complete resection can cure this benign lesion. The disease may occasionally recur, and follow-up should be carried out after surgery.