What is Histiocytosis
What is Histiocytosis?
Histiocytic Disorders and Rare Diseases – together we will find a cure!

Histiocytosis is an umbrella term applied to a group of rare diseases, characterised by increased numbers of white blood cells called histiocytes in the blood and tissues. In all forms of histiocytosis, these cells, which are part of the protective immune system, begin to attack the body, targeting many organs of the body including the bone marrow, liver, spleen, lungs, skin, bone and brain. The prognosis for patients varies greatly depending on the form of histiocytosis.

There are two main groups.
The first group is called a dendritic cell disorder, and the most common disease in this group is Langerhans Cell Histiocytosis (LCH) previously known as Histiocytosis X. Also included in this group are more rare diseases, juvenile xanthogranuloma (JXG) and Erdheim-Chester Disease (ECD).

Langerhans Cell Histiocytosis, LCH for short, histiocytes called Langerhans cells, which are normally found in the skin, may spread to many organs and damage them, so that the symptoms vary depending on which organs are affected, but skin rashes, destruction of bone, breathing problems and damage to the brain are common.

LCH occurs in children, often during infancy but also in adults. It is usually a chronic disease and may cause severe disabilities due to brain damage. The diagnosis is made by microscopic examination of a tissue specimen obtained by biopsy. The prognosis depends very much on the extent of disease and organs affected, which can be assessed by imaging studies. LCH is thought to be caused by alterations in the DNA of Langerhans cells.

The second group is called a macrophage cell disorder, and includes primarily Haemophagocytic Lymphohistiocytosis (HLH) and Rosai-Dorfman Disease (RD).

How to explain Histiocytosis

How to explain Histiocytosis

Haemophagocytic Lymphohistiocytosis HLH for short. In this disease a virus infection triggers another type of histiocyte, the macrophage, to become over active and attack the body. Red blood cells and other white blood cells are engulfed and destroyed by the macrophages, so that the patient is unable to fight infections.


Patients therefore suffer from high fevers, may become anaemic and often have skin rashes, as well as symptoms due to the infecting virus. HLH is an acute and life threatening disease. It frequently occurs in childhood but may occur at any age.

Diagnosis depends on detection of the infecting organism and demonstration of macrophages engulfing other cells as well as other abnormalities of white blood cells, usually in sample of bone marrow. In familial forms of HLH, abnormal genes, which alter white blood cell function, are passed from the parents to children.

Rarer Forms - there are other even rarer forms of histocytosis related to both LCH and HLH and very rarely malignant histiocytosis occurs, which is a leukaemia-like disease of histiocytes.

Please be advised that all the information you read here is not a replacement for the advice you will get from your consultant and their team.

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Frequently Asked Questions

Histiocytic Disorders and Rare Diseases

Why are all of these diseases with different names considered to be related to each other?
All of the diseases are caused by the over-production of white blood cells called histiocytes. Their different classifications depend on the type of histiocyte involved.

Where can I find reliable information about histiocytosis?
Histiocytosis UK online community provides a number of informational documents and articles, as well as links to medical articles about the histiocytic disorders. While the Internet does provide a significant volume of information about histiocytic disorders, some of this information is not accurate. It is important to look for documents that are current, are free of grammatical and spelling errors, appear to be objective, are free of advertisements, and clearly state their sources.

How to explain Histiocytosis

How to explain Histiocytosis

How can I explain histiocytosis to family and friends?
Histiocytosis is a rare disease that is caused by the over-production of a type of white cell that can lead to organ damage and the formation of tumors. The Histiocytosis UK FAQ pages are also a great way to help explain these complicated diseases to family and friends.


What is Rare Disease?

  • A rare disease is defined by the European Union as one that affects less than 5 in 10,000 of the general population.
  • There are between 6,000 and 8,000 known rare diseases.
  • Around five new rare diseases are described in medical literature each week.
  • 1 in 17 people, or 7% of the population, will be affected by a rare disease at some point in their lives.
  • This equates to approximately 3.5 million people in the UK and 30 million people across Europe.
  • In the UK, a single rare disease may affect up to about 30,000 people.
  • The vast majority of rare diseases will affect far fewer than this – some will affect only a handful, or even a single person in the whole of the UK.
  • 80% of rare diseases have a genetic component.
  • Often rare diseases are chronic and life-threatening.
  • Rare diseases can be single gene, multifactorial, chromosomal or non-genetic.
  • 75% of rare diseases affect children, and 30% of rare disease patients die before their fifth birthday.

Where can I learn more about rare diseases in general?
Rare Disease UK (RDUK) is the national alliance for people with rare diseases and all who support them. www.raredisease.org.uk.
Orphanet – Database/information about rare diseases with translation available in numerous languages. http://www.ojrd.com
Please be advised that all the information you read here is not a replacement for the advice you will get from your consultant and their team.

Help ensure that we can continue to bring you this vital informational material, make a donation today

LCH Newsfeed

pubmed: histiocytosis

NCBI: db=pubmed; Term=histiocytosis

Related Articles

Eosinophilic granuloma of the cervical spine in adults: A review.

World Neurosurg. 2019 Feb 13;:

Authors: Prasad GL, Divya S

PURPOSE: Spinal eosinophilic granulomas(EGs) are uncommon tumors, constituting <1% of all bone tumors. They are mostly seen in the pediatric age group while adult onset is rare. Cervical spine is an infrequent location for involvement by EG. Available literature remains sparse regarding the clinical and management aspects of these lesions, especially in adults.
MATERIALS AND METHODS: Literature review was performed by searching online databases to analyze all the reported cases of adult onset cervical EG.
RESULTS: Sixty-two cases were identified and analysed. The male:female ratio was 3.1:1. The mean age at presentation was 32.8years(range18-71 years). Neck pain, limb weakness and restriction of movement were the most frequent symptoms. C2 vertebra was the most frequently involved. Vertebral body was involved in >80% cases and only two had vertebra plana morphology. The cervical lesions involved single vertebra in 42(82%) cases while 9(18%) cases had multiple vertebral involvement. Fifteen patients were managed conservatively, of whom seven failed requiring surgery later, 40 cases underwent definitive surgery and 17 received adjuvant treatment. Posterior-only surgeries were performed in 5, anterior-only in 20, and circumferential in 14 cases. The mean follow-up duration was 68 months (12-268months). Outcome was good to excellent in all, except one, irrespective of type of treatment received.
CONCLUSIONS: Cervical spine EG is rare in adults and usually presents as an osteolytic lesion involving the vertebral body and vertebra plana is very rare. Surgery is typically reserved for cases with severe neurological deficits and bony instability. Outcome appears good in majority of the cases.

PMID: 30771538 [PubMed - as supplied by publisher]

Related Articles

A novel fixation technique using anterior C1 screw in a pediatric solitary cervical spinal juvenile xanthogranuloma.

Eur Spine J. 2019 Feb 15;:

Authors: Rajasekhar R, Karthigeyan M, Salunke P, Gupta K

PURPOSE: Juvenile xanthogranuloma (JXG) presenting as solitary vertebral body lesion is infrequently seen and usually limited to one or two levels. We report a case of an isolated JXG with extensive cervical spinal (bony and extradural) involvement in a 6-year-old child. There was a diagnostic dilemma as the radiologic and intraoperative picture resembled tuberculosis. The spinal reconstruction was also challenging due to involvement of multiple vertebral levels and necessitated an anterior C1 screw.
METHODS: The lytic lesion was multicompartmental, involving the craniovertebral junction and the subaxial spine (till C6 vertebral body) and extending into the retropharyngeal space. Noticeably, an associated thoracic syringomyelia was also present. Near-total excision of the lesion and 360° spinal fixation was performed using fibular strut graft. The graft was cranially anchored to the C1 anterior arch, thereby sharing the load with the posterior occipito-cervical instrumentation in order to avoid a construct failure due to cantilever effect.
RESULTS: At 12-month follow-up, the patient had good clinico-radiologic outcome with evidence of bony fusion and resolution of syrinx.
CONCLUSION: The report highlights the diagnostic dilemma of JXG lesion on both the radiology and surgery and discusses the challenges in the management and the relevant literature. The described technique can be a viable option in pediatric tumors with extensive C2 vertebral body involvement. Occasionally, extradural compression can have associated syrinx formation and the primary treatment per se could tackle the underlying syringomyelia.

PMID: 30771048 [PubMed - as supplied by publisher]

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