A young patient with lower limb Ewing's sarcoma experienced a cerebral infarction: A care-compliant case report.

RATIONALE: Ewing sarcoma (ES) is a rare bone tumor that most often occurs in adolescents and young adults and is a malignant tumor that mainly affects, bones and soft tissues.[1] Trousseau syndrome refers to a series of blood clot events in veins and arteries that occur during malignant tumor progression due to problems with blood clotting and breakdown. It includes clinical manifestations such as pulmonary embolism, arterial thrombosis, deep vein thrombosis, and nonbacterial thrombotic endocarditis. Acute cerebral infarction can also occur as part of Trousseau's syndrome. Due to the rarity of ES and the lack of information on late-stage patients, there are reports of ES leading to acute cerebral infarction. PATIENT CONCERNS: A 41-year-old male patient with lower limb osteosarcoma suddenly experienced a cerebral infarction. DIAGNOSES: Lower limb juvenile sarcoma combined with Trousseau syndrome, cerebral infarction. INTERVENTIONS: An emergency cerebral angiography, mechanical thrombectomy, and percutaneous superselective arteriography. OUTCOMES: The patient was conscious, spoke fluently, and had grade IV muscle strength in the left upper limb. The left lower limb had limited movement because of the tumor, but basic activities had returned to how they were before the illness. The patient is currently undergoing further treatment for left lower limb osteosarcoma. LESSONS: This reports a case of lower extremity elephantiasis nostras combined with Trousseau syndrome that was complicated by acute cerebral infarction. Clinically, acute cerebral infarction resulting from ES is rare. This case report aims to increase clinicians' awareness of this disease and enhance diagnostic accuracy. This article presents only a single case report, with certain limitations, and more cases need to be observed in clinical practice to inform clinical diagnosis and treatment.