What level is the CRF and where and how big is the cyst? It may be that the severity of the CRF is such that a surgery attempt could kill the cat and the vet knows that. If its stage 3 or 4 CRF, anesthesia may be too risky.
If its beyond the skill of the vet, yet possible to do, look for specialty vets at higher level referral centers or veterinary schools. Ex Internal med, surgery specialities.