Hi @luft80. I just ran across this article listing top specialized hospitals worldwide. I sorted by speciality to find top 150 gastroenterology. Mayo tops the list and there are several closer to you in Spain, even Barcelona. The article explains ranking criteria and I do not know more beyond that. It may be worth digging into some of them a bit.

Newsweek Worlds Best Specialized Hospitals: https://rankings.newsweek.com/worlds-best-specialized-hospitals-2026/gastroenterology

I am interested to hear more as you take steps through the process of finding a top specialist for your son’s collagenous gastritis. Please come back and update.