Castleman disease is an atypical lymphoproliferative disorder where the immune system becomes highly activated and attacks vital organs by producing cytokines and other factors.

“So basically, a pathologist looked at my lymph node and they thought I had lymphoma, but they figured it was a really aggressive lymphoma, which is a form of cancer. But they looked at it and just like Benjamin Castleman did, looked at it and said, "This doesn't look like lymphoma. This actually looks different. It looks like this thing called Castleman disease," which is basically what we call an atypical lymphoproliferative disorder. So, it's kind of like lymphoma, but it's got features that are more like an autoimmune disease, and so basically your immune system becomes highly activated and starts attacking all your vital organs.”