Sometimes physicians may note a finding on a test, but because of a lack of up-to-date information, dismiss the finding. This, then, can unfortunately be perpetuated, if the physician passes on her report to other physicians evaluating your symptoms.
An example is people with Tarlov cysts or meningeal cysts. There is evidence that these cysts can cause excruciating pain and neurological disability which disrupts the life of those living with these cysts. If you were to explore recent studies, it’s clear that these cysts cause great suffering and disability, but that newer radiological and surgical procedures can bring significant relief for the majority of people.
In the literature, however, these cysts are often dismissed (still) as being incidental findings of questionable significance. In other words, even if you have a diagnosis that “fits” your symptoms, your symptoms may be dismissed, and as such, the diagnosis missed. And with a misdiagnosis, the loss of effective treatment follows.