Twenty-three years follow-up after low-dose Gamma Knife surgery of a brainstem juvenile pilocytic astrocytoma: a case report and review of the literature Abstract Juvenile pilocytic astrocytoma (JPA) is a World Health Organization (WHO) grade I tumor that is the commonest to occur in the 0–19 age group, with an excellent prognosis of 96% 10-year survival in pediatric patients. Complete resection is the treatment of choice for JPAs. However, this is not always feasible due to the location of certain tumors, and the management following subtotal resection is controversial. Fractionated radiotherapy, chemotherapy, radiosurgery, and observation have all been used to treat tumor remnants. We report a young patient with good tumor control 23 years following low-dose Gamma Knife surgery (GKS) of a subtotally resected brainstem JPA and recommend that GKS may be a feasible treatment option to achieve long-term tumor control when subtotal resection cannot be achieved, even if the GKS prescription dose must be significantly reduced due to large tumor volume or proximity to critical structures sensitive to radiation.