Tumor progression and transformation of low-grade glial tumors associated with pregnancy.

Brain tumor growth or progression has been shown to occur in low-grade glial tumors and meningiomas. While progression has been documented in this population, transformation to a more aggressive high-grade glial tumor that can lead to increased morbidity and mortality has not been identified. In this case series, we document transformation from low-grade gliomas to high-grade gliomas (WHO grade III and IV) in young women during pregnancy. We further discuss the possible etiologies of this phenomenon.