Pilocytic Astrocytoma in Type 1 Neurofibromatosis (NF1) Syndrome

Abstract

A 21-year-old female, who had prior stereotactic biopsy for cerebral glioma 3 months ago, presented with generalized tonic-clonic seizures, multiple café au lait macules on the trunk, and a positive first-degree family history of von Recklinghausen’s disease (Type 1 Neurofibromatosis-NF1). She was treated with upfront (primary); Linac-based SRS for mixed cystic-solid, right, fronto-parietal pilocytic astrocytoma (WHO Grade I). Only the solid tumor component was targeted. The target volume of 5.3 cc received a marginal dose of 15.0 Gy normalized to 80% isodose line. At 5 months post-SRS, the patient developed contralateral moderate hemiparesis, probably attributed to the focal mass effect of tumor pseudo-progression and increased peritumoral vasogenic edema, which required treatment with steroids and diuretics. This neurological deficit showed progressive improvement starting at 12 months post-SRS because of a marked progressive decrease in tumor size and vasogenic edema as shown in subsequent follow-up MRIs. At last radiological follow-up (122 months post-SRS), MRI showed markedly decreased tumor size, with only residual small enhancing lesion in T1 Gadolinium-enhanced study, sustainable complete disappearance of the cystic tumor component, and residual minimal perilesional edema in T2 and FLAIR studies. Serial post-SRS follow-up MRIs showed a decrease in size of both the solid and cystic tumor components. At last clinical follow-up (122 months post-SRS), the patient had sustainable control of seizures without anticonvulsant medications and residual minimal left-sided body weakness, not interfering with normal daily activities.