Anybody ever had a syrinx?

[mrsm12]

My dm was having a shooting pain high in her back and was eventually referred for an mri, gp rang with the results Friday evening and said she had a moderately wide syrinx not sure at what level. The gp had never heard of it so said she'd ring her back today. I'm a nurse and have never heard of it either so after a quick Google I'm worried, we are going to push the gp for an urgent referral today but if anybody has any personal experience good or bad id appreciate it, thanks