Arginine Vasopressin Deficiency in Children with Craniopharyngioma and Cerebral Germ Cell Tumour: Two Sides of the Same Coin. Clinical and Radiological features.

Introduction: Paediatric brain tumours in the sellar-suprasellar region (SSR) are often associated with arginine vasopressin peptide deficiency (AVPD), either at diagnosis caused by the tumour itself or during follow-up as consequence of treatments. The purpose of this research is to retrospectively describe the neuroradiological characteristics and the timing of AVPD development in a cohort of paediatric patients with craniopharyngioma (CP) or germ cell tumours (GCT).

Methods: We evaluated brain MRI at tumour diagnosis and at the onset of AVPD, as well as recorded clinical, endocrinological and histopathological data, treatments, and outcome.

Results: Seventy-two patients with AVPD 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%). No statistically significant differences were noted in tumour size between CP and GCT. Posterior pituitary bright spot absence was reported at diagnosis or at follow-up (as surgery consequence) in all patients with AVPD, indicating that the absence of hyperintensity is a cardinal feature of AVPD. When measurable, pituitary stalk was thickened in most GCT patients (61.5%). At AVPD diagnosis in GCT, the mean age was 11.9 years; 18 (69%) patients had AVPD at the time of tumour diagnosis, 5 (19.3%) before the diagnosis with a latency of 24.4 months (range 4-48), and 3 (11.5%) during follow-up (mean 24 months, range 4-60) due to tumour recurrence. GCT patients presented with severe endocrinological manifestations (18/26), headache and vomiting (10/26), visual impairment (5/26) and behavioural changes with fatigue (1/26). In CP, the mean age at AVPD diagnosis was 10.3 years; 7 (15.2%) patients had AVPD at time of tumour diagnosis, 37 (80.5%) developed it shortly after neurosurgery and 2 patients (4.3%) after 2 and 4 months from surgery, respectively. Clinically, 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. While the vast majority of CP patients (93%) received only surgery, all GCT patients received radiation therapy in addition to or instead of surgery.

Conclusion: An early differential diagnosis in children with AVPD and brain tumours is supported by a good understanding of the clinical features and imaging findings. Expert follow-up is necessary.