In the last two years, there has been a significant increase in the number of pediatric thyroid cancer patients coming to the hospital than before. I was impressed by an 8-year-old boy who came from rural Anhui province. One day his mother happened to notice several lumps on the child’s neck, which were hard to touch, and brought him to the hospital for examination. After some related tests, the result was diagnosed as thyroid cancer with lymph node metastasis. Since he was the only child in the family, his parents had him in their 40s, and his father was a son-in-law, the child took his mother’s surname, it was like a bolt from the blue for the family when they learned that the child had thyroid cancer, and it was hard to accept the fact. There are many other cases like this, and most of them are only children nowadays. Once diagnosed with “cancer”, it is really a big blow to the family. As a doctor specializing in pediatric oncology for 30 years, I would like to tell parents that pediatric oncology is not a “devil”, and with early detection and reasonable and standardized treatment, children can get rid of cancer and grow up, study and become adults like normal children. In general, thyroid cancer is fast-growing, hard and uneven on the surface, and many patients may have lymph node metastasis on the side of the neck; ultrasound examination of thyroid gland shows unclear borders, abnormal aspect ratio, poor elasticity and sand-like calcification foci. Thyroid cancer in children accounts for 0.5%-3% of malignant tumors in children. In general, over 90% of thyroid cancer in children is differentiated thyroid cancer. This disease progresses less rapidly and may not have any clinical manifestations in the early stages. Compared with adults, thyroid cancer in children has a lower mortality rate and a significantly better long-term survival rate than adults. However, thyroid cancer in children is multifocal in nature, i.e. there are multiple lumps, involving both lobes of the thyroid gland, and most of the primary tumor foci are large, and metastases to the neck, mediastinal lymph nodes and lungs are likely to occur. The impact of thyroid cancer on children’s growth and development, school life, and survival is very dangerous. The risk of thyroid cancer to children is also related to the degree of differentiation of the tumor. A well-differentiated thyroid cancer grows slowly, such as papillary thyroid cancer, and can survive for many years without endangering life, while a highly malignant thyroid cancer, such as undifferentiated cancer, can lead to the death of the child in a short time. The overall prevalence of thyroid masses in children is significantly lower than that of adults, but the proportion of malignancy is significantly higher. The exact cause of thyroid cancer in children is unknown and may be related to abnormal exposure to radiation, excessive or deficient iodine intake, genetic factors, etc. Among them, we can see evidence that those with a family history of thyroid cancer have a significantly higher rate of thyroid cancer in their offspring. On the other hand, in the former Soviet Chernobyl nuclear leak contaminated area, the percentage of children with thyroid cancer was significantly higher than before the nuclear leak, and many of them could be traced to a history of frequent or excessive exposure to radiation. Therefore, in clinical care, many experienced physicians will try to avoid or reduce the exposure of children to radiation. The relationship between too much or too little iodine intake and the development of thyroid cancer has not been conclusively established.