People often confuse tumor with cancer, thinking that tumor is cancer and cancer is tumor, but in fact, there is a fundamental difference between the two. Tumors include benign tumors and malignant tumors, and those with malignancy in between are called “junctional tumors”, so tumors are not equal to cancer. There are more than 1000 kinds of malignant tumors, which are divided into two categories, namely cancer and sarcoma. The naming principle is that according to the site of occurrence and tissue origin, those with the word “cancer” or “sarcoma” after their names are malignant tumors. Malignant tumors growing in epithelial tissues are called “cancer”. The so-called epithelial tissue refers to the cells distributed on the surface of human body and all the cavities of human body, such as cavity, esophagus, stomach, intestine, etc. If malignant tumors grow in these organs, they are called oral cancer, esophagus cancer, stomach cancer, intestine cancer, etc. All malignant tumors occurring in human connective tissues such as fat, muscle, bone, lymph and hematopoietic tissues are collectively called “sarcoma”, such as liposarcoma, smooth muscle sarcoma, bone sarcoma, lymphosarcoma and so on. People often confuse benign tumors with malignant sarcomas, such as liposarcoma and smooth muscle tumor, which are all benign tumors. However, once the word “meat” is added to their names, such as liposarcoma and fibrosarcoma, they are malignant tumors. Therefore, it is a big mistake to treat sarcoma as benign tumor. There is another kind of malignant tumor from multiple tissues, which is neither called cancer nor sarcoma, but the word “malignant” is added in front, such as malignant mixed tumor. All malignant tumors derived from embryonic cells or immature tissues are called “maternal cell tumors”, such as hepatoblastoma and medulloblastoma. In addition, there are a few malignant tumors that still use their customary names, such as Hodgkin’s disease, non-Hodgkin’s disease, leukemia and melanoma. Therefore, malignant tumors are not always called “cancer”. Benign tumors are organisms that grow on the surface of the body or in the organs, resembling tumors but not having the biological characteristics of malignant tumors. The medical naming principle for benign tumors is to add the word “tumor” after the name of the site of occurrence, for example, a tumor in the bladder is shaped like a nipple, so it is named “papilloma of the bladder”. If the tumor originates from connective tissue, the word “tumor” should be added directly after the name of the tissue, such as fibroma, lipoma and hemangioma. As the saying goes, there is a difference between benign and malignant tumors, and they should not be confused. In addition, it is difficult to determine whether the tumors between benign and malignant are truly benign or malignant. This third type of tumor is called “intermediate tumor”, “junctional tumor”, “borderline tumor”, “potentially malignant tumor”, “semi-malignant tumor”, etc. It is more often called “junctional tumor”. Characteristics of junctional tumors: 1. The morphology of tumor cells is between benign and malignant, so there are differences in pathological diagnosis and two schools of thought in clinical practice, which is the characteristic of its atypical differentiation. 2.There is a tendency of local diffusion in the growth pattern. After local excision according to benign tumor, it is often prone to local recurrence, but no metastasis, or very little metastasis, or even if there is local metastasis, it still progresses slowly and is not a big threat to the patient. The actual manifestation has local spread or occasional metastasis, or cell morphology is consistent with malignancy, but there is no obvious spread of metastasis and other malignant manifestations. Malignant tumors usually grow rapidly, infiltrate and destroy the surrounding tissues without envelope or with only pseudo-envelope, poorly differentiated, with tissue and cell morphology far from their corresponding normal tissues, showing heterogeneity, disturbed arrangement, irregular nuclei shape, often with different degrees of deep staining, increased nucleoli, and pathological nuclear division; secondary changes such as hemorrhage, necrosis, cystic changes and infection appear in the tumor. The nucleus is often irregular in shape, and the nucleus nuclei are enlarged and increase and appear pathological nuclear division. After surgical resection, the tumor often recurs and metastasizes easily, causing extensive damage to surrounding tissues. If not treated in time, it often leads to death. The distinction between carcinoma and sarcoma is of great clinical significance. Cancer is mostly seen in middle-aged and elderly people over 40 years old, and lymphatic system metastasis is common; while sarcoma is mostly found in young people, and bloodstream metastasis is mostly seen.