Posterior Sphenoid Retention Cyst

I was just diagnoses with a mass or cyst in the posterior sphenoid region.  The cyst is 2.5cm and 2.7cm in width.  I was wondering if this is a serious condition and what does it mean for me as far as surgery.  Report also said moderate mucosal thickening in the ethmoid region. I have been thru chemo and have had problems since.  I was told my sinuses were more than double the normal size.  How do you fix all this.  What does it all mean as far as treatment or to correct the problem.  Someone please fill me in.  My appt. with ENT is not for a while.  I would just like to know more about it.