Lesions of the hypothalamus and pituitary stalk are rare in adolescence. Congenital and acquired, benign and malignant lesions occur, and the spectrum of diagnoses differs from that in adults, with inflammatory conditions occurring less frequently.
Lesions that develop in the hypothalamus may extend to the pituitary and present with features of pituitary hormone deficiencies, including arrest of growth and puberty in the adolescent age group, or visual disruption. Diabetes insipidus is more likely to be present at diagnosis of hypothalamic tumours than in patients with primary pituitary lesions. Features of raised intracranial pressure may be present if the foramen of Monroe is obstructed. The hypothalamic syndrome of morbid and escalating obesity, disruption of the sleep wake cycle, adipsia, temperature dysregulation and cognitive and behavioural disturbance may be present at diagnosis, or develop following treatment, and is especially challenging to manage.
Developmental abnormalities that impinge on the pituitary stalk include Rathkes cleft cysts, epidermoid and arachnoid cysts. Incidental findings of pituitary stalk thickening on an MRI performed for unrelated reasons pose a particular challenge, as normative data for the dimensions of the pituitary stalk in childhood and adolescence are not robust, and biopsies of the pituitary stalk may readily disrupt pituitary function. Neoplastic lesions of the pituitary stalk are more likely to be present in patients with diabetes insipidus, and in this age group the most common diagnoses include germ cell tumours and Langerhans cell histiocytosis. Lymphoma may also develop in this region.
In this talk we will use clinical cases to consider the challenges of diagnosis and management of young people with tumours in these regions.