Nine-Year Follow-Up of Gamma Knife Surgery for Hemangioblastomas in von Hippel–Lindau Disease: Illustrating the Challenge of Distinguishing Radiosurgical Effect from Natural Tumor Quiescence

Background/Objectives: Hemangioblastomas are rare, benign, highly vascular tumors of the central nervous system, frequently associated with von Hippel–Lindau (vHL) disease. Case Presentation: We report a 16-year-old female with vHL presenting with recurrent headaches, abdominal distension, and ocular discomfort. Imaging revealed hemangioblastomas in the fourth ventricle and retrobulbar space, alongside multiple pancreatic cysts. The patient underwent three sessions of Gamma Knife Surgery (GKS) with initial tumor regression and symptom relief. However, long-term follow-up demonstrated progressive disease, with new lesions in the cerebellum, spinal cord, and orbit, including cystic transformation. Histopathology confirmed the reticular variant of hemangioblastoma. Despite further radiosurgical and surgical recommendations, the patient and family opted for conservative management, with lesions remaining radiographically stable over nine years. Conclusions: This case demonstrates that Gamma Knife Surgery may provide temporary local disease control for selected solid hemangioblastomas in von Hippel–Lindau disease but does not alter the underlying disease course. Long-term radiographic stability should be interpreted cautiously, as hemangioblastomas exhibit saltatory growth patterns that make it difficult to distinguish treatment effect from natural tumor quiescence. These findings emphasize that radiosurgery should be regarded as a disease-control strategy rather than curative therapy, underscoring the importance of individualized management, multidisciplinary decision-making, and prolonged surveillance.