ESPE Abstracts

Introduction: Paediatric brain tumours in the sellar-suprasellar region (SSR) are often associated with central diabetes insipidus (CDI), either at diagnosis caused by the tumour itself or during follow-up as consequence of treatments.

Aims: To define the timing of CDI onset and radiological features on brain MRI in our cohort.

Methods: We retrospectively analysed paediatric patients with CDI and craniopharyngioma (CP) or germ cell tumours (GCT) diagnosed at King’s College and Royal Marsden Hospitals between January 1996 and December 2022. We evaluated brain MRI at tumour diagnosis and at the onset of CDI, recording clinical, endocrinological and histopathological data, treatments, and prognosis. MRI features evaluated were tumour size (volume and diameters) and epicentre; posterior pituitary bright spot and pituitary stalk thickness.

Results: 72 patients with CDI were included: 46 CP (M: F=25:21) and 26 GCT (M: F=18:8). CPs were suprasellar (63%), sellar (4%) or both (33%). GCTs were suprasellar (65%), pineal (24%) or bifocal (11%). In CP the mean age at CDI diagnosis was 10.3 years. 7(15.2%) patients had CDI at tumour diagnosis, 37 (80.5%) developed CDI soon after neurosurgery and 2(4.3%) after 2 and 4 months respectively from surgery. In CGT the mean age at CDI diagnosis was 11.9 years; 5(19.3%) had CDI before tumor diagnosis with a latency of 24.4 months (range 4-48), 18(69%) at tumour diagnosis, while 3(11.5%) during follow-up (24 months, range 4-60), due to tumour recurrence. Bright spot absence was reported at diagnosis or at follow up (as surgery consequence) in all patients with CDI. Fourteen GCT patients showed pituitary stalk thickening at diagnosis: between 3-4.5 mm (19.2%), between 4.5-6 mm (19.2%) and >6 mm (23.1%). In the remaining patients with GCT (38.5%) the pituitary stalk was normal (< 3mm). Headache and visual abnormalities were the most frequent clinical symptoms at diagnosis of CP (39/46, 84.8%), with hydrocephalus (16/46, 35%) and displacement of optic chiasm (29/46, 63%) at the initial MRI. GCT patients presented with endocrinological manifestations (10/26), headache and vomiting (10/26), visual impairment (5/26) and behavioral changes with fatigue (1/26). The main endocrinological disorders were CDI (18/26, 69%), central adrenal insufficiency (16/26, 61.5%), and central hypothyroidism (17/26, 65%).

Conclusion: A good understanding of clinical characteristics and imaging features in CDI in children with brain tumors helps achieving an early differential diagnosis and accurate therapeutic strategies. Specialist follow-up is required.