A 14-year-old girl with anorexia nervosa (AN) was found to have an intracranial neoplasm. Atypical psychological symptoms prompted further evaluation, including electroencephalogram and neuroimaging, which revealed a sellar and suprasellar mass.This patient had an eating disorder and a brain tumor, which appear to be two unrelated conditions. However, it remains unclear how each affected the other. The diagnosis of AN, like all other psychiatric disorders, requires that possible medical etiologies and coexisting medical problems be excluded. AN and other eating disorders are particularly difficult to diagnose in children and adolescents because they often do not present in the manner typical of adults. Perceptual and cognitive disturbances associated with AN are difficult to evaluate because children and adolescents normally change over time as they progress through different stages of development. Therefore, It is particularly important to evaluate for the presence of medical conditions when a diagnosis of an eating disorder is made in a child or adolescent.