There is no clear evidence that growth hormone replacement therapy for treatment-related growth hormone deficiency in patients with childhood intracranial malignancies has a role in tumour relapse or second malignancy. A 16-year-old girl with an intracranial germinoma was treated with local radiotherapy and subsequently received growth hormone replacement therapy as an adult. Three years after starting growth hormone therapy, 23 years after her radiotherapy treatment, the patient's tumour recurred. Surveillance requirements for patients receiving growth hormone in this setting are discussed.