What is non-Langerhans cell histiocytosis?
The term ‘non-Langerhans cell histiocytosis’ refers to a group of conditions called histiocytoses that are caused by an overgrowth of cells called histiocytes. Non-Langerhans cell histiocytosis has this name to differentiate it from Langerhans cell histiocytosis. There are two subtypes of non-Langerhans cell histiocytosis: • Class IIa: histiocytosis involving dermal dendritic cells • Class IIb: histiocytosis involving cells other than Langerhans cells and dermal dendrocytes The subtypes can be told apart by their different appearance and special staining of tissue examined under a microscope. Like other forms of histiocytosis, non-Langerhans cell histiocytosis tends to cause reddish-brown or reddish-yellow bumps in the skin and may affect internal organs (such as liver, kidneys, lungs).
