What Could Cause The Left Side Of The Throat To Be Enlarged And How Can It Be Diagnosed And Treated?

Hi I would like to briefly ask a question following on from the last question I asked the doctor about my moms throat which she had been seen in the ent department for a persistent sore throat lasting for few weeks,was sent for mri of neck went back to see the doctor at ent department who had told my mum they had noticed an enlarged left side of her throat showing up on MRI, so the left side was slightly larger than the right side the doctor was unsure as to what this may be and wanted to look down mums throat with some sort of tube device inserted into the nose mum refused as was panicking about this procedure as I (her daughter) was not there to support her at the time I was at work, we now have another appointment booked to see the same doctor I m going with her this time.My question is should this be something to be worried about like cancer or anything as mum said she doesn t think the word lump was mentioned just enlarged left side of her throat which I think the doctors was a little unsure what it was??