Hepatocellular carcinoma can be divided into five categories according to the morphology of the naked eye.
(1) diffuse type, in which small cancer nodules are diffusely distributed throughout the liver; (2) mass type, in which the diameter of the tumor is between 5 and 10 cm, and according to the number and morphology of the masses, there are single mass type, fused mass type, and multiple mass type; (3) giant mass type, in which the diameter of the tumor is greater than 10 cm; (4) nodular type, in which the diameter of the tumor is between 3 and 5 cm; (5) small cancer type, in which the diameter of the tumor is less than 3 cm and the border is clear.
Hepatocellular carcinoma can also be divided into five categories according to the tissue arrangement and cellular characteristics.
① Beam-like type: the most common histological type of HCC. ② pseudoglandular and glandular vesicular type; ③ dense (solid) type; ④ sclerotic type; ⑤ other types: purpura-like, chrysanthemum-like, spontaneous necrosis and other different types of tumor components.
Hepatocellular carcinoma cytological typing
(1) Hepatocellular type: the most common type, the cancer cells are polygonal in shape, similar to normal liver cells, but the cancer cells are significantly larger in size.
(2) Clear cell type: More than 50% of the cancer cells are rich in glycogen in the cytoplasm, and the cytoplasm may be lightly stained and filamentous, or transparent.
③Spindle cell type: It accounts for about 5% of hepatocellular carcinoma, and about 46% of patients have positive serum alpha-fetoprotein (AFP). This type often shows portal vein invasion and intrahepatic metastasis, and has a poor prognosis.
④Lipid-rich type: It is caused by the disorder of fat metabolism of cancer cells, and is easily misdiagnosed as benign lesions, such as focal steatosis.
Differentiation and grading of hepatocellular carcinoma.
Grade Ⅰ: Cancer cells are highly differentiated, similar to normal hepatocytes, with thin beam type arrangement. The rate of surgical resection is high and the chance of postoperative survival is high.
Grade II: Cancer cells are moderately differentiated, with morphology close to normal hepatocytes, but with increased nuclear/pulp ratio, deepened nuclear staining, increased cytoplasmic eosinophilia, and pseudoglandular ductal structure on top of beamy type. The resection rate of large hepatocellular carcinoma is obviously reduced and the chance of recurrence within a short time after surgery is high.
Grade III: Cancer cells are poorly differentiated, nuclear volume and nuclear staining are more than grade II, nuclear heterogeneity is obvious, nuclear schizophrenia is common, and tumor giant cells are seen. Radical resection cannot be performed, or cancer infiltration can be seen at the cut edge; Grade IV: the most poorly differentiated cancer cells, with irregular shape, highly heterogeneous cancer cells in the majority, and loosely arranged cells. More vascular cancer thrombi or satellite foci can be seen microscopically, with intra- and extra-hepatic metastases.
Small hepatocellular carcinoma.
It refers to hepatocellular carcinoma with single nodule diameter or the sum of two adjacent carcinoma nodules diameter ≤ 3 cm, with few cancer emboli visible to the naked eye and clearly demarcated from surrounding liver tissues.
Intrahepatic cholangiocarcinoma.
Intrahepatic cholangiocarcinoma accounts for 2.3% of malignant tumors of the liver. The exact etiology is unknown, and studies suggest that polygenic variants play an important role in the multi-stage development of intrahepatic cholangiocarcinoma.
Intrahepatic cholangiocarcinoma is most commonly seen in the left outer lobe of the liver, with a tumor diameter of 2-15 cm, which can encapsulate the involved bile ducts, and the liver tissue is often bilious and rarely cirrhotic.
Microscopically, the typical intrahepatic cholangiocarcinoma is a moderately differentiated adenocarcinoma with cuboidal or low columnar shape, cytoplasm free of bile, clear nuclear membrane, inconspicuous nucleoli, and common nuclear division.
Histologic types: The common histologic types of intrahepatic cholangiocarcinoma are ductal adenocarcinoma, papillary adenocarcinoma or beam-cord type. Poorly differentiated adenocarcinomas include polymorphic, glandular follicular, mucinous, indolent cell and spindle cell types.
Treatment and prognosis: Overall, intrahepatic cholangiocarcinoma is more malignant and treatment is preferred to surgical resection, which can generally improve the average survival to 2 years.
Mixed type of hepatocellular carcinoma.
It consists of a mixture of two components, hepatocellular carcinoma and intrahepatic cholangiocarcinoma, and the incidence is less than 5% of liver tumors. The incidence is less than 5% of liver tumors. The main manifestation is that within a single tumor node, both components of hepatocellular carcinoma and intrahepatic cholangiocarcinoma are either mixed or partitioned, and genotypic analysis shows two separate clones. Mixed hepatocellular carcinoma is a highly aggressive tumor with a 5-year postoperative survival rate of 24%, which may be worse than that of hepatocellular carcinoma alone (37%), and is treated with the same principles as hepatocellular carcinoma.
Hepatoblastoma.
Hepatoblastoma is an embryonal malignant tumor of the liver, accounting for 50%-62% of primary malignant tumors of the liver in children, with 70% and 90% of children under 2 and 5 years of age, respectively, with an average age of 16 months and a male-to-female ratio of 2:1. 5%-96% of children have elevated serum methemoglobin levels. The tumors are mostly located in the right lobe of the liver and are mainly single large solid masses with solid lobulated sections or localized cystic changes due to hemorrhage and necrosis, and hard and calcified when they contain bony components. Half of the tumors have a fibrous envelope, and the liver tissue is not cirrhotic.
Microscopically, they can be divided into epithelial type (56%) and mixed epithelial-mesenchymal type (44%).
Epithelial type.
①Fetal type: the most common type, accounting for about 31%, with tumor cells resembling 6-8 week old fetal hepatocytes, round or rectangular, smaller than normal hepatocytes, arranged in 1~2 layers of cell-thick beams, alternating with each other to form characteristic bright and dark structures.
The tumor cells are more poorly differentiated, lacking interconnectivity, and usually arranged in irregular cords, strips, glandular vesicles, and chrysanthemum clusters. The tumor cells have poorly defined borders, sparse cytoplasm, basophilic, increased nuclear/pulp ratio, and nuclear schizophrenia. The embryonic type and fetal type are often mixed.
The tumor cells are arranged in the shape of beams with more than 10 layers of cell thickness, which is a more mature differentiation of hepatoblastoma.
④Small cell undifferentiated type: accounting for 2% to 10%, it is the most poorly differentiated tissue type of hepatoblastoma. The tumor cells are small round or ovoid, with loose lamellar or nest-like distribution due to poor connectivity, little cytoplasm, and unclear cell borders.
Mixed epithelial-mesenchymal type.
It consists of a variable number of fetal or embryonic epithelial cell components mixed with mesenchymal components of the three germ layers. The most common mesenchymal components are bone-like tissue and focal calcifications deposited around the tumor cells.
Fibrous lamellar type carcinoma.
Fibrous lamellar type carcinoma is very rare in this country. In the United States, this tumor accounts for 1% of all hepatocellular carcinomas. Patients are predominantly young, with more than 90% occurring in people under 35 years of age. Most patients do not have cirrhosis, and serum fetoprotein is not elevated in 85% to 90% of patients, while serum carcinoembryonic antigen (CEA) levels may be elevated.