Author: Dr Amy Stanway, Dermatology Registrar, Nottingham United Kingdom, 2005. Revised by Dr David Lim, Dermatology Registrar, Auckland, New Zealand, August 2011
Non-Langerhans cell histiocytosis may also be called ‘class II histiocytosis’, ‘non-X histiocytosis’, and ‘histiocytosis of mononuclear phagocytes other than Langerhans cells’.
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 subgroups of non-Langerhans cell histiocytosis:
Class IIa: histiocytosis involving dermaldendritic cells
Class IIb: histiocytosis involving cells other than Langerhans cells and dermal dendrocytes
The subgroups can be separated 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).
Class IIa non-Langerhans cell histiocytosis
Class IIa histiocytosis involves dermaldendritic cells. The cells are called ‘dendritic’ because they have dendrites or long branch-like processes. Class IIa histiocytosis may affect children and adults.
Juvenile xanthogranuloma and related conditions
Progressive nodular histiocytosis
Benign firm papule or nodule, usually found on lower limb but may arise on any site
Tends to persist longterm
No treatment is required in most cases, but may be surgically removed to confirm diagnosis or if desired
Subtypes include benigncephalic histiocytosis, generalised eruptive histiocytoma and papular xanthoma
Presents in infants and young children with raised reddish-yellow or reddish-brown bumps mostly on the head and upper body
Rarely affects other organs in the body although this is not usually serious. Eye involvement may occur in children less than 2 years of age and is important to detect as it can cause blindness if not treated early
Usually no treatment is recommended for skin lesions as these disappear by themselves within 1 to 6 years. Involvement of internal organs may respond to radiotherapy, surgery or chemotherapy if required.
Skin lesions usually consist of hundreds of small yellowish-brown or reddish-brown bumps, which are usually evenly spread on both sides of the face and trunk and may form sheets of thickened skin. They may particularly affect the armpits and groins.
30% of affected people have involvement of the lining of the mouth, airways or eyes (mucosal surfaces). Wartyplaques in the mouth are called verruciform xanthomas.
40% of affected people develop diabetes insipidus, a condition that results in inability to control water loss (resulting in continual thirst and excessive urine production). This is due to histiocyte overgrowth on the lining of the brain (meninges).
May affect internal organs (such as liver, lungs, kidneys etc.)
Self-limiting and eventually improves by itself but may persist for many years.
Characterised by hugely swollen lymph glands (usually in the neck), a fever and blood abnormalities (neutrophilia, anaemia, and raised ESR)
Almost half of affected individuals have involvement of other organs in addition to lymph gland involvement
Any organ can be involved but common sites are the skin (10%), mouth/nose/windpipe (upper respiratory tract), the eye, salivary glands, bone and brain
Skin lesions are non-specific multiple small papules usually on the face
Treatment may not be required for mild disease. More severe disease may respond to surgery or radiotherapy.
Overall the prognosis is good and in many people this disease may disappear by itself. Very severe disease with involvement of many internal organs may be fatal (particularly if there is involvement of the immune system).
Usually presents in older adults with multiple yellowish bumps or large flat thickened areas. These can ulcerate.
Occur particularly around eyelids but may also affect other sites.
General symptoms include tiredness, vomiting, blood-noses, back pain and Raynaud phenomenon.
Other organs may be involved, particularly the eye, liver and spleen.
Paraproteinaemia (an abnormal antibody in the blood) is found in 80% of affected people, sometimes associated with multiple myeloma (a blood malignancy).