Diencephalic syndrome in childhood craniopharyngioma--results of German multicenter studies on 485 long-term survivors of childhood craniopharyngioma.

CONTEXT: Childhood craniopharyngiomas (CPs) are known to be associated with an increased risk of excessive weight gain and hypothalamic obesity. Atypical clinical manifestations include the development of a diencephalic syndrome (DS) with a failure to thrive or maintain weight at appropriate body mass index. CASES AND METHODS: In a retrospective study, we analyzed 21 of 485 childhood CP patients (4.3%) who presented with a low weight (< -2 body mass index SD) at the time of diagnosis. Eleven of the 21 patients were identified with a DS due to proven hypothalamic involvement. We show the clinical manifestations of DS and weight development before and after diagnosis in these 11 patients. The first significant differences between patients with low weight at diagnosis and normal-weight patients at diagnosis are observed at 5 years of age. Within the first 2 years after diagnosis, the weight of DS patients and normal-weight patients converge to a similar level. Tumor size does not play a role with respect to DS development. Finally, tumor characteristics of DS patients were compared with magnetic resonance imaging scans of obese CP patients at the time of diagnosis.
CONCLUSIONS: DS is a rare clinical manifestation in childhood CP and should be considered as a discrete diagnosis in failure to thrive. DS at the time of diagnosis does not preclude weight gain after diagnosis of a CP with hypothalamic involvement.