Hepatoblastoma

　　1. Etiology

　　The etiology may be the abnormal development of embryonic connective tissue, which is a malignant tumor originating from the liver embryonic primordial cells. Neonates may develop it in utero, with some literature reporting its occurrence in a fetus at 7 months of gestation. Adults may develop malignant tumors after many years of embryonic-type hepatic cells in the liver.

　　2. Pathogenesis

　　Hepatoblastoma mostly occurs in the right lobe of the liver, with about half of the cases involving both lobes or being multicentric. It is generally solitary, round, with clear boundaries, and the tumor diameter varies from 5 to 25 cm. The gross appearance of the tumor is related to the mesenchymal tissue components such as bone-like, cartilaginous, or fibrous tissue contained within. Generally speaking, the tumor presents as rough nodular or lobulated elevations on the liver surface, with clear boundaries, half of which have a capsule, and a relatively hard texture. The color of the tumor ranges from brownish to grayish white, with a uniform and consistent texture in the cross-section, which may occur with hemorrhage, necrosis, and calcification, but is usually not accompanied by liver cirrhosis. Under the microscope, the tumor is composed of epithelial components and stromal variant components at different stages of maturation. According to the degree of differentiation of the tumor cells, it can be divided into fetal type (highly differentiated type), embryonic type (lowly differentiated type), and mixed type.

　　1. Fetal type:The fetal-type hepatic cells are smaller than normal liver cells,呈多边形, with clear cell boundaries, acidophilic granular cytoplasm, and may have vacuoles. The nuclear-cytoplasmic ratio is 1:4 to 1:2, and the nucleus is round or oval, with chromatin of uneven thickness, containing a single nucleolus, and nuclear division figures are rare. The cells are arranged in two-layered irregular hepatic cell bundles, with sinusoids between the bundles. The analysis of nuclear DNA content in hepatoblastoma cells shows that the fetal type is mostly diploid.

　　2. Embryonic typeThe embryonic-type hepatic epithelial cells have poor differentiation, small size, fusiform shape, blurred cell boundaries, little cytoplasm, and a nuclear-cytoplasmic ratio of 1:1 to 2. The nuclear chromatin is rich, the nucleolus is large and distinct, and nuclear division figures are easily visible. This type of cell has poor adhesion ability and often clusters into rose petal-like shapes or connect into loose cord-like structures. The analysis of nuclear DNA content in hepatoblastoma cells shows that the embryonic type is mostly aneuploid, and aneuploid tumors are prone to vascular invasion, with poor prognosis. Common extracorporeal metastases include the lung, abdominal lymph nodes, and brain.

　　3. Mixed type:Mixed-type hepatoblastoma also contains other mesenchymal components, such as osseous tissue, cartilage, striated muscle with fine stripes, squamous cell foci, keratin pearls, etc.

　　Occasionally, large tumors may rupture, causing symptoms and signs of acute abdomen.

　　There are also some children with congenital malformations, such as cleft palate, macrostomia, maldevelopment of the auricle, absence of the right adrenal gland, umbilical hernia, cardiovascular malformations, or renal malformations, etc.

　　The gross appearance of the tumor is related to the mesenchymal tissue components such as bone-like tissue, cartilage, or fibrous tissue contained in it. Generally speaking, the tumor presents as rough nodular or lobulated protrusions on the surface of the liver, with clear boundaries, half with a capsule, relatively hard texture, and the color ranges from brownish to grayish white. The cross-section is uniform in texture, and bleeding, necrosis, and calcification may occur, and liver cirrhosis is often not present.

　　The etiology is not yet clear. Referring to the general prevention methods of tumors, understanding the risk factors of tumors, and formulating corresponding prevention and treatment strategies can reduce the risk of tumors. There are two basic clues for preventing the occurrence of tumors: even if tumors have already started to form in the body, they can also help the body improve its resistance. These strategies include:

　　1. Avoiding harmful substances (carcinogenic factors) is to help us avoid or minimize contact with harmful substances.

　　2. Enhancing the body's immune resistance to tumors can help improve and strengthen the body's immune system in the fight against tumors.

　　Patients with hepatoblastoma should pay attention to supplementing sufficient high-quality protein in diet adjustment, with animal protein such as chicken, fish, and milk being preferable, and plant protein such as beans being better. Ingredients such as ginseng, American ginseng, Astragalus, jujube, fish maw, turtle, and longan can be selected to promote cell proliferation; patients with chemotherapy often have anemia, and iron-rich foods should be given to them; cancer patients need 5-10 grams of vitamin C per day to support the function of leukocytes and red blood cells, and to prevent the side effects of chemotherapy drugs. It is recommended to eat more vitamin-rich foods, drink more green tea, and enhance the efficacy of chemotherapy drugs in killing cancer cells.

   　1. Treatment

　　Surgical resection is the most effective treatment method, often supplemented by chemotherapy, radiotherapy, or immunotherapy. If a hepatoblastoma can be resected, the prognosis is better than that of primary hepatocellular carcinoma, with about 1/3 of patients surviving for 5 years. Hepatoblastoma is often not accompanied by liver cirrhosis, and the tumor is mostly solitary, with a complete capsule, and can be resected by left or right lobe resection, with the maximum resection volume reaching 75% of the whole liver. Therefore, a positive attitude should be adopted in the treatment of this disease, and efforts should be made to achieve complete resection. A report on 57 cases of primary liver cancer in children, including 16 cases of hepatoblastoma, all of which were successfully resected, with no surgical deaths. 11 patients have survived for more than 6 years. The longest surviving case was a 11-month-old male infant with a giant right liver tumor, who underwent right hemihepatectomy. The tumor weighed 810g, and the pathological diagnosis was hepatoblastoma. The patient has been healthy for 16 years since the operation.

　　For patients with large tumors or satellite lesions, postoperative systemic chemotherapy should be combined to improve the postoperative survival rate of patients. Chemotherapy mainly involves the combined use of doxorubicin and cisplatin, with good efficacy. Other drugs include vincristine, cyclophosphamide, and fluorouracil (5-Fu), etc. Pulmonary lobectomy can be performed for solitary pulmonary metastases, which can extend survival. For patients with bilateral or multiple pulmonary metastases, systemic chemotherapy can be applied, with good recent efficacy.

　　II. Prognosis

　　If the tumor is solitary, small in size, superficial in location, and without extrahepatic metastasis, surgical resection can achieve cure. More than half of the patients have lost the opportunity for surgical treatment by the time of their visit, and those who can be resected also have a poor prognosis. Liver blastoma is insensitive to radiotherapy and chemotherapy, so the prognosis of the disease is poor. For the early-stage and low-grade fetal and mixed types without metastasis, the long-term survival rate of surgical resection varies from 15% to 37%. The long-term survival rate after tumor resection and comprehensive treatment has been reported to reach 80%. Gao Ya et al. reported that 29 cases of pediatric liver blastoma were divided into early stage (surgical resection from 1965 to 1980), middle stage (surgical resection + postoperative chemotherapy from 1980 to 1991), and late stage (preoperative chemotherapy + surgery + postoperative chemotherapy from 1991 to 1995). The overall resection rates in the early and middle stages were 37.5% and 30%, respectively, and the overall 1-year tumor-free survival rates were 25% and 30%. The overall resection rate in the late stage was 62.5%, and the 1-year tumor-free survival rate was 50%. Data show that the improved survival rate in the later stage is due to the use of preoperative chemotherapy, which increases the number of cases of advanced tumor resection; it is believed that strengthening the preoperative chemotherapy for stage III and IV tumors is the key to improving their resection rate and improving the overall prognosis of the disease.