When would you consider obtaining tumor tissue in NF-1 associated pediatric low grade glioma?

This is definitely an evolving field. Recently, a consensus paper discussing this and other NF-related topics was published that may be helpful as below:

Packer RJ et al., Implications of new understandings of gliomas in children and adults with NF1: report of a consensus conference. Neuro Oncol. 2020

In general, many would argue that if an NF1-Associated LGG looks atypical on imaging or is behaving atypically, one should consider a biopsy if safe and feasible. There is no specific time frame to site that has been studied, but many would argue that a lesion that is assumed an NF1-associated low-grade glioma that is not responding to therapy (as most do) or is growing rapidly (as most do not), a biopsy is helpful for 2 reasons. The first is t...