Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. With your son s diagnosis of oligodendrolioma already being known in the left occipital lobe. What I can tell you is that I can virtually guarantee that your son s left hand symptom is NOT from that tumor. However, if your son were in my care I would immediately obtain an MRI with gadolinium contrast looking for something (possibly related to this oligo as a 2nd lesion) in the left fronto-parietal region. I would also have him undergo a PET scan. I hope I have answered you query. If you have any further questions you can contact us in every time.