D47: Other neoplasms of uncertain or unknown behaviour of lymphoid, haematopoietic and related tissue

D47.0: Histiocytic and mast cell tumours of uncertain and unknown behaviour

The bone marrow is inside bone. The blood cells are formed in the bone marrow of some of the bones. There are 3 different types of blood cell: red blood cells, white blood cells and platelets. Red blood cells are important for carrying oxygen in the blood. White blood cells are part of the body’s immune system. They fight pathogens. Platelets are important for clotting blood.

There are various kinds of defense cells (immune cells) in the blood. Each of these types has specific tasks. You have too many of a certain type of defense cell. These defense cells release substances that can lead to symptoms. You can then have itching, headache, hot flashes or gastrointestinal discomfort, for example. In your case, no one knows exactly how the disease will go on to develop. It is not known whether the disease is benign or malignant.