Diencephalic Syndrome in Adolescents: A Case Series.

Introduction: Two pediatric patients presented with unintentional weight loss despite normal caloric intake. Both patients later developed neurological symptoms, and a neoplastic lesion was detected in the hypothalamic-optic chiasmatic region. The location of the tumor and the significant weight loss aligned with diencephalic syndrome (DES), which typically occurs in infants and young children. However, both patients were in their teens and thus greatly deviated from the normal age range of this disorder. Methods/Results: After chart review we analyzed the patients with a focus on the similarities in their clinical course and final diagnosis. Both patients were ultimately diagnosed with DES. Managing the patients' tumors allowed them to experience significant weight gain and return to daily life activities. Discussion: Although the exact pathogenesis for DES is not fully understood, the symptoms are associated with hypothalamic dysfunction. DES has been accepted as a disorder of the hypothalamic hunger and satiety control mechanisms. With both patients having tumors in the hypothalamic-optic chiasmatic region, it is expected that the growing mass would compress the hypothalamus and disrupt normal hypothalamic function. Because of the hypothalamus' role in hunger and satiety control mechanisms, it is logical that these disruptions could produce abnormal weight changes. Conclusion: DES is a rare condition and typically only presents in infants and toddlers. Thus, this syndrome occurring in teenage populations represents a rare diagnosis in an unexpected demographic. The novelty of this presentation led to delays in diagnosis and effective treatment. Greater awareness of the occurrence of DES in atypical demographics is needed to ensure proper patient management.