Objectives: This study aimed to assess the diagnostic value of Symmetrical Claustrum Sign（SCS） in children with febrile infection-related epilepsy syndrome (FIRES), describe the clinical features, treatment responses, and prognosis of children with FIRES accompanied by Symmetrical claustrum lesions (FIRES-C). Methods: A retrospective cohort study conducted at Beijing Children\'s Hospital from January 2015 to April 2024 included children with \""febrile and convulsions\"" who met the inclusion criteria. The diagnostic efficacy of SCS was calculated by analyzing the sensitivity and specificity . Results: The study enrolled 1,105 patients, including 129 with FIRES, 35 of whom were diagnosed with FIRES-C (median onset age: 8.3 years; males: 18).In the cohort of patients with status epilepticus (n = 347), the sensitivity of SCS was 27 .1% (95% confidence interval [CI], 19.8%–35.9%), and the specificity was 95.4% (95% CI, 91.8%–97 .4%). The median time to develop bilateral claustrum lesions was 15.8 days（IQR 11-19）. The results of the MRI scans revealed that 7 patients (20%) had isolated claustrum lesions, while 28 patients (80%) had extra-claustrum lesions. After a median follow-up of 42 months, 14 out of the 29 patients (48.3%) who survived exhibited moderate to severe deficits (mRS ≥ 3), and 2 patients died. No significant differences in prognosis were observed between the two groups (P=0.322). Significance: SCS exhibit high specificity but limited sensitivity in the diagnosis of FIRES inpediatric patients. SCS may serve as a biomarker to assist in the diagnostic process and is typically associated with a less severe clinical progression.