The young protagonist of this article is Xiaoyu, who turned 3 years old this year. Like other children, Xiaoyu had been enjoying his childhood carefree until mid-May, when everything before became gradually distant and left him. In mid-May this year, Xiaoyu repeatedly developed a cough with fever and shortness of breath, and his parents treated him at the local hospital for a common “cold”. This startled the parents. According to this result, “closed chest drainage” was done in the hospital to try to drain the fluid in the chest cavity, but after 7 days of treatment, no significant improvement was seen, so the family asked to be transferred to Children’s Hospital. After the transfer, he continued to perform “anti-inflammatory, support and closed drainage of the chest cavity,” but still did not see significant improvement, so the decision to do surgery, the operation saw a large number of “fish jelly-like tissue” in the chest cavity, the pathological laboratory results are: adenoid rhabdomyosarcoma, which is a kind of malignant Such a result was like a bolt from the blue, almost knocking Xiaoyu’s parents down, but they endured their grief and never showed it in front of Xiaoyu, in order to let Xiaoyu establish confidence in overcoming the disease, while often washing their faces with tears behind their backs, their eyes flushed. Xiaoyu’s post-operative recovery was poor, with a daily drainage of more than 200 ml, the color was also slightly bloody, and the loss of pleural fluid meant the loss of a lot of protein, so Xiaoyu needed a daily infusion of one or two bottles of albumin to strengthen his nutritional status. Not one to give up lightly, the father took the pathology results to a pediatric hospital in Shanghai to seek any better treatment, but the answer he received did not give him a hint of joy. The helpless family decided to do chemotherapy at the children’s hospital, but just one day before preparing for chemotherapy, Xiaoyu’s condition suddenly changed and he was urgently transferred to the intensive care unit, where again photos and ultrasound were examined and the results reported: a large number of solid shadows in the right lung field, disappearance of the diaphragmatic surface, displacement of the left side of the mediastinum, ultrasound: right hollow occupancy of the chest and ascites. Faced with such a result, the parents knew that Xiaoyu’s condition was deteriorating at an accelerated rate, and in a desperate situation, they chose to give up treatment and take Xiaoyu home. Rhabdomyosarcoma is a common soft tissue malignant tumor in children and adolescents, ranking 3rd after neuroblastoma and Wilms cell tumor among extracranial tumors, accounting for 6% to 7% of all tumors in children and 40% to 50% of all soft tissue tumors. In the United States, the incidence rate under 15 years old is 4~7/1 million, of which, 2/3 are under 6 years old, and the male to female ratio is 1.3~ Rhabdomyosarcoma of the thorax is extremely rare, appearing in multiple parts of the chest, such as the chest wall, lungs, heart, mediastinum and septum. The prognosis for rhabdomyosarcoma of the chest is poor, with reports that only 30-40% of patients have access to treatment, and most die within 2 years from local and distant metastases. Treatment of rhabdomyosarcoma is tricky, and the treatment of RMS remains a major challenge for surgeons and oncologists. The International Rhabdomyosarcoma Study Group (IRSG) recently published a 3-year survival rate of only 86% for metastasis-free RMS, which is currently based mainly on its clinical stage and pathological type. The main factors affecting the prognosis of RMS are the site of origin of the tumor, clinical stage, surgical resection, type of pathology, and response to the first radiotherapy and chemotherapy. The purpose of telling this case that we saw not long ago is to let parents pay attention to observation, raise vigilance and achieve early detection, early diagnosis and early treatment of some diseases.