LCH is an unusual condition. It has some characteristics of cancer but, unlike almost every other cancer, it may spontaneously resolve in some patients while being life-threatening in others.
LCH is classified as a cancer and sometimes requires treatment with chemotherapy. LCH patients are therefore usually treated by children’s cancer specialists (paediatric oncologists/ haematologists). The vast majority of children will recover completely from LCH.
Langerhans refers to Dr Paul Langerhans, who first described the cells in the skin which are similar to the cells found in LCH lesions.
Histiocytosis refers to histiocytes which are cells that are part of the immune system, and are found in many parts of the body.
There are two types of histiocytes:
- macrophage/monocyte cells – these destroy harmful proteins, viruses and bacteria in the body
- dendritic cells – these stimulate the immune system.
Langerhans cells are dendritic cells and are normally only found in the skin and major airways. In LCH, the abnormal dendritic cells that look similar to Langerhans cells may be found in different parts of the body, including the bone marrow, skin, lungs, liver, lymph glands, spleen and pituitary gland. When these abnormal dendritic cells accumulate in these tissues, they may cause damage.
LCH is divided into two groups:
- single-system LCH – when the disease affects only one part of the body, for example the skin or the bone
- multi-system LCH – when it affects more than one part of the body.