Yeah, this is how this occurs. An initial scan or two can either miss a small finding or misinterpret it as incidental. Then on a later scan when the new diagnosis is obvious, the previous findings in retrospect are traced to the current finding.
There are only three ways to act on an abnormal imagine study.
1. Ignore it ( bad option).
2. Biopsy it ( which would injure a lot of healthy people if every spot was biopsied, especially in an organ like the brain)
3. Repeat the study at a future interval to see if it changes. If so, this adds more credence to #2.
In this case, it looks like the image was asked to be repeated and it was not. This can happen if the first MRI was done at say an ER, and then the patient goes back to the primary doc and communication about the recommendation to repeat the study was not made.
Apparently it had been scanned several times, as it says the doctor said all of the scans show it going back 12 years. You must remember that getting a scan done in G.B. is not like it is done here. You have to wait several months, perhaps even years to get it done, which may explain the 4 year separation from 2010 to 2014. Free healthcare is not what the leftists want you to believe it is.
While what you say is true, do you not think that the doctor should have said something such as, we see something suspicious so I want you to have another scan done in a year?