Three cases of behavioral disorders in children previously treated for a diencephalic tumor are reported. In such cases, classical psychiatric evaluation is difficult because reference data on childhood psychoorganic syndromes are lacking. Another complicating feature is that multiple factors contribute to the impairment of social interactions, including maladaptive reactions to disease-related stress, sensory deficits, and cognitive disorders. A structured evaluation should be performed in order to assess the child's behavior, the psychological and educational environment, and impairment of neuropsychological and neurophysiological function.