Malignant Conversion to Glioblastoma in Neurofibromatosis Type I-associated Pleomorphic Xanthoastrocytoma: Unknown Predictors of Favorable Outcome

Pleomorphic xanthoastrocytoma (PXA) is a benign glial tumor, the association of which with neurofibromatosis type I (NF-1) has been often reported in the literature. Although malignant conversion to glioblastoma may be seen in 5%–10% of PXA, the same has been reported only once in the presence of NF-1. We report, so far known to be only the second such case all over. A 25-year-old male, a known case of NF-1, underwent frontal craniotomy for a superficially located right frontal lesion, histology of which suggested PXA. Two years later, the lesion recurred and the subsequent surgery revealed malignant conversion to glioblastoma. After adjuvant radiotherapy, the patient now continues to do well and is free of disease after another 3 years of follow-up. We believe that if low levels of neurofibromin are seen in such cases with malignant conversion, subsequently increased neurofibromin levels may be responsible for better overall survival in these patients.