@lornabaxter I wasn't familiar with your diagnosis, but I found some interesting research studies. The first one discusses treatment and what specialists should be consulted, I think you should be seen by specialists in different disciplines as differing viewpoints can often find a more comprehensive solution if they work together. That is exactly what they do at Mayo, and these different specialties consult with each other as to what is best for the patient.

I am a Mayo spine surgery patient, and that is how they evaluated my case, and my neurosurgeon even received a phone call with results of a test completed by another specialist right before his appointment while I was there at his consultation. It's a team approach and they put the patient first. Your ENT is putting himself first, and possibly it maybe profit motivated. At Mayo, all staff are employees and not owners of private practices looking for financial gain, so that does not affect their medical decisions. As a patient, you have the right to multiple medical opinions, and you can fire a doctor who is not serving you. I hope your insurance allows you to make your own choices in specialists. You can always call the insurance company and ask about your options for consultations. Personally, I wouldn't trust a doctor who is going behind your back and cancelling referrals to other specialists who might take the treatment of the case away from him causing a loss of his potential income. You have to chose what you think is right for you based on medical opinions and you should be allowed as many opinions as you need to make an informed choice.

I am an artist, but I have a biology degree and worked in research for a neuro-anatomist at a university, and I look for research studies in literature to figure things out. I did this for my own case on spinal cord compression that had some unusual symptoms, and I found what 5 local spine surgeons missed. I contacted a surgeon at Mayo with that information, and he helped me. I had to advocate for myself. Coming to Mayo changed my life and I wish I had come there first. If coming to one of the Mayo Clinic campuses is possible for you, I would recommend it. They see many more patients with rare conditions than most medical centers. Here is my Mayo story if you are interested. https://sharing.mayoclinic.org/2019/01/09/using-the-art-of-medicine-to-overcome-fear-of-surgery/

Here is the research literature I found for you on Empty Sella Syndrome.
https://academic.oup.com/jcem/article/90/9/5471/2838746
https://journals.sagepub.com/doi/abs/10.1177/194589240301700205
https://www.jstage.jst.go.jp/article/nmc/45/8/45_8_428/_article/-char/ja/