ECD is a histeocytic neoplasm. Basically, one with this cancer overproduce wbc/lymphocytes/macrophages and tumors are formed in major organs. I currently have kidney involvement. i was diagnosed at Mayo in April of this year. i see Dr Ron Go. i orginally had cardiac involvement but have responded to zelboraf. About 50% have the BRAF mutation. i orginally had a major sore throat and then 3 days later a UTI and felt something was wrong. The docs in my home town area could not figure it out so i traveled to Mayo. This disease has varied presentation and less than 1000 people in the world have been diagnosed.