, I can understand your terror, it is a high lesion count. But there are things you can do about this. Your wife's disease-modifying therapy might not be doing its job. There are more than 21 different treatments to choose from now and they should be discussed with your doctor.
I don't know what your relationship with this doctor has been like, whether he has been a concerned physician or controlling and distant. His odd behavior seems to be either a misguided attempt to shield you and your wife from feeling terrified, or a cold-blooded power play. You would know better than I. Either way, he was wrong to lie and withhold medical information that belongs to your wife.
I'm not a doctor and cannot interpret your test results, but we know that if a new scan shows a much higher lesion count than the previous one, that could be evidence of radiological progression.
You didn't mention whether your wife's symptoms have worsened. If they have then that could be a sign of clinical progression.
In either case, your neuro should talk to you about changing your disease-modifying therapy. Whatever drug she is taking, it hasn't been effective in preventing new lesions. That is very concerning.
You might bring up these concerns at her next appointment. If your wife did have "only" 10-16 new lesions, that would also be a sign that the drug might not be doing its job.
I hope you will find some answers very soon. Please give us an update and we will be here for you and help if we can.
Kim