Background <p>Children with malignant solid tumors often experience cognitive, emotional, sleep, and fatigue-related problems, but the structural relationships among these symptoms domains remain insufficiently understood. This study used network analysis to characterize the multidimensional symptom network, identify structurally important nodes, and compare network heterogeneity across clinical subgroups to inform stratified supportive care.</p> Methods <p>Using convenience sampling, we recruited 230 children aged 6–18 years with malignant solid tumors from a tertiary children’s hospital in Chongqing, China. Cognition, emotion, sleep, and fatigue were assessed using the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) Chinese version (short form), the Generalized Anxiety Disorder-7 (GAD-7), the Patient Health Questionnaire-9 (PHQ-9), the Sleep Disturbance Scale for Children (SDSC), and the PedsQLTM Multidimensional Fatigue Scale (PedsQLTM MFS), respectively. A Gaussian graphical model was estimated, followed by analyses of centrality, bridge centrality, network stability, and subgroup network comparisons.</p> Results <p>Children with malignant solid tumors showed a substantial multidimensional symptom burden. Sleep problems had the highest prevalence (63.48%), followed by anxiety (51.74%), depression (29.13%), and below-average cognitive performance (44.78%, FSIQ &lt; 90), together with a relatively high fatigue burden. In the symptom network, “Disorders of Excessive Somnolence” (S5-DOES), “Disorders of Initiating and Maintaining Sleep” (S1-DIMS), and “Cognitive Fatigue” (F3-CF) showed high centrality. Among the bridge metrics, “Cognitive Fatigue” (F3-CF) was the most prominent, followed by “Anxiety” (E1-Anx) and “Disorders of Initiating and Maintaining Sleep” (S1-DIMS). Subgroup comparisons indicated significant differences in both network structure and global strength between tumor-type groups, whereas cognitive-status groups differed primarily in network structure, underscoring clinical heterogeneity in symptom organization.</p> Conclusions <p>Cognitive, emotional, sleep, and fatigue symptoms in children with malignant solid tumors formed an interconnected multidimensional symptom network. Sleep-related symptoms and “Cognitive Fatigue” (F3-CF) showed high structural importance and may be candidate targets for priority monitoring and supportive care. Network heterogeneity by tumor type and cognitive status further suggests that symptom assessment and management may need to begin earlier and be tailored by clinical subgroup. These findings require validation in larger, longitudinal studies.</p> Graphical Abstract <p></p>