Histiocytosis
About Histiocytosis
Histiocytosis is a group of rare diseases that most often affect young children, but can occur at any age. There are two main types of histiocytosis: Langerhans Cell Histiocytosis (LCH) and Hemophagocytic Lymphohistiocytosis (HLH). These diseases have in common the abnormal growth and accumulation of certain cells of the immune system. LCH and HLH differ in the type of cell that is growing abnormally and in the clinical consequences of that abnormal cell growth. The Histiocytoses are not considered to be cancers, although they can be life-threatening and chemotherapy is often required to treat them.
The two types of histiocytosis are:
Langerhans Cell Histiocytosis (LCH) primarily affects children under the age of 15 years. In this disease, Langerhans cells grow abnormally due to changes that are not currently well understood. Patients exhibit symptoms related to accumulation of these cells in different parts of the body, including the bones, lungs, bone marrow, lymph nodes, skin, liver and brain.
Hemophagocytic Lymphohistiocytosis (HLH) usually affects infants and very young children. In rare cases it can affect adolescents and adults. Patients with HLH have an abnormally regulated immune system, and specific white blood cells, called macrophages, grow abnormally and accumulate in the body's organs, including the liver, spleen, bone marrow, central nervous system and skin.
