I had already had many GYN problems, a long list since puberty actually. However, when GCT showed up I already had a polycystic ovary that was non functioning. The GCT showed up there & it's my belief these two are related.
I had my period at the wrong time despite being on a hormone regimen. I knew something was wrong at that point. Turned out my uterus was quite enlarged even though I had no pain. My surgery started out to remove my enlarged uterus, but then the entcapsulated GCT was found. My entire reproductive system was removed at that point.
I advise to listen to your body, it often gives you some kind of signal when something is wrong. If the first doctor isn't listening to you, get a second opinion or a third.