There is no such term as “the most serious”, and it should be determined according to the specific conditions of patients. Diffuse hepatocellular carcinoma refers to the malignant transformation of liver cells in a diffuse state, and there are multiple cancerous transformations in the liver, which is a type of hepatocellular carcinoma. Hepatocellular carcinoma is a kind of malignant tumor occurring in the liver, which can be classified into infiltrating type, expanding type, infiltrating-expanding mixed type and diffuse type according to the growth mode. Diffuse hepatocellular carcinoma is characterized by the emergence of a large number of small nodules in the liver, spreading all over the liver, with a diameter of less than 1cm, and not fusing with each other. Diffuse hepatocellular carcinoma is mostly caused by viral hepatitis, alcohol consumption and other factors, and common clinical symptoms include ascites, pain in liver area and jaundice. If diffuse liver cancer is diagnosed, one should go to the hospital in time for consultation, and under the guidance of doctors, chemotherapy, targeted or immunotherapy should be carried out, etc. During the treatment, one should keep an optimistic mindset.