Pilocytic astrocytoma with anaplastic features presenting good long-term clinical course after surgery alone: a case report

Purpose: Pilocytic astrocytomas (PAs) are the most common brain tumor in children and typically have an excellent prognosis. However, some PAs show histologically anaplastic features. It is reported that PAs with anaplastic features often need the postoperative radiation and chemotherapy due to aggressiveness such as early local recurrence and dissemination. We describe an interesting case of primary anaplastic PA with good clinical course in the long-term. Methods: A 10-year-old man presented with worsening headache and vomiting. Magnetic resonance imaging (MRI) showed a large cystic tumor with contrast-enhanced solid component in a right occipital lobe. Magnetic resonance spectroscopy (MRS) showed the decrease of N-acetylaspartate (NAA) and the increase of choline and lipids, which suggested the malignancy. Results: The patient was operated with an occipital lobectomy. The tumor was incompletely resected due to the deep invasion to the inner wall of lateral ventricle. Pathological diagnosis was a pilocystic astrocytoma with anaplastic features. Although aggressive features were suspected from magnetic resonance spectroscopy and pathological findings, the remnant tumor showed no recurrence for 8 years without any postoperative treatments. Conclusion: PAs could exhibit variable behavior, and careful managements including wait-and-scan should be considered, because adjuvant therapies may cause child’s growth disorder and malignant transformation.