Histiocytosis is a mysterious disease that in a lot of ways resembles cancer.
It causes cells to multiply wildly and takes the body hostage. But unlike cancer, very little research has been done on it. And if you're the parent of a child with histiocytosis that means you've got a lot more questions than you do answers. And arms and his head had sores all over it. They're growing faster or differently than one would normally expect.