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1.The history suggest presence of the
sinus mass lesion and been on chemo and
radiation - possibility could be growth of the mass.
2.If doctor has asked about the
stroke history means there could be involvement of any vessels.
3.Probably there is intracranial involvement - and occluding some vessels.
4.There might be signs of stroke in the brain - that might be chronic which patent not experienced.
5.Sinec he had to cancers known , possibilities of metastasis could be considered.
6.I have only given possible causes - do not take any thing serious - wait for report. Hope the best. Good luck.
Hope i have answered your query.
Any thing to ask do not hesitate. Thank you.