What is leptomeningeal myeloma? Is it the same as CNS myeloma? How common is it?

What is CNS myeloma? CNS myeloma is very rare. It is a subset of what's called extra medullary disease, which is plasma cells present outside of the bone marrow. And those usually go to multiple sites. The skin is common, the liver, the lymph nodes. The CNS is not a very common site of extra medullary disease. It can occur early on, very rare, and it can occur when the disease comes back at relapse. There is really no incidence for it, so I cannot tell you the percentage of people that get that condition. It's case reports. And usually, if you look in the literature, there are many definitions of CNS myeloma. I will be talking about a very specific subset, which includes myeloma affecting the brain, affecting the covering of the brain, which is called lipdomyelmial disease, which is lipdomyelmial myeloma, or affecting the CNS, which is the fluid covering the brain. There are myeloma that occurs in the skull, the cranium, and extend into the brain. Those patients, in some studies, are counted as CNS myeloma, but really they are not, because those patients do very well when they receive radiation or systemic treatment. To diagnose brain myeloma, as you called it, or lipdomyelmial myeloma, we need two things. Number one, imaging, and the standard imaging is MRI, and also we need pathology, meaning we need to get a CSF, or put a needle in the back of the spine, to get small amount of fluid from around the brain to see if there is any plasma cells in it. And if we find plasma cells, that will define CNS myeloma.