I can't remember if edema is a possible symptom of MM. But I know it is a possible side effect of some of the drugs used to treat MM. I have edema in my legs and arms. It's not serious in the arms; it's more noticeable in my lower legs. I wear compression socks to reduce the risk of blood clots, but they are also helpful at reducing edema.
*At this point I got way off-topic. I got back on with what immediatly follows. The off-topic material can be seen further below.
Bone-marrow edema sounds to me like the cause of bone pain which is a common symptom of MM. As the malignant plasma cells increase in number, they displace (push aside) normal bone marrow tissue. One result of this can be hydraulic pressure inside the bones that pushes outward, causing pain. I did not know that I had had bone pain until it went away during the first four-five months of chemo therapy. By the time I had started my stem cell transplant, I was experiencing less pain that I had in years. No way of proving it, I suppose; but I am convinced that it was bone pain caused by this hydraulic pressure, which stopped when the cancerous plasma cells were killed.

*(With the following I got way off the original topic. I was saying that I wear compression socks every day to try to prevent blood clots.)
The blood clot issue is very important to me because MRI's have twice found pulmonary embolisms. The second MRI found only one, but the first one found several in each lung. During a followup visit with my PCP two weeks later, he congratulated me for surviving! I am blessed to still be alive.
Blood clots are a possible side-effect of Pomalyst, which I was taking at the time. Pomalyst is similar to the drugs Thalimid and Revlimid. I now take Ninlaro; blood clots are not a side effect of Ninlaro, not so much, anyway. It's better known for causing peripheral neuropathy.
Blood clots in the legs can break loose and get lodged in the lungs or the brain. If the clot is big enough, it can block the flow of blood through the pulmonary artery (I suppose this is correct) into the lungs, depriving the body of oxygenated blood. This is a deadly turn of events. Death can occur within minutes. A cousin of mine died this way. So . . . well, it's something I still don't take seriously enough. It is a powerful reason to lose weight, or should be. I need to lose about 12-1/2% of my body weight. That's my goal, anyway. Maybe the counselor I started meeting with last Wednesday will be helpful with this.
God bless you all. Have a good week.
Donnie

Yes my husband has had it and has had too wear support hose or socks as it went up his calves it was edema and then upon further ct scan they found a blood clot in his left leg as well.

I looked this up. Bone marrow edema is diagnosed with an MRI. LadyT, my ankles were swollen when I went through induction. I think it was Velcade and all those steriods. 🤔

Swelling in your ankles

Ok wow ok thank you continued prayer i did the leg tests i didn’t have a tumor but so many tests keep saying edema besides my legs and feet stay swollen