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

Pulmonary Langerhans cell histiocytosis in adults: A case report.

World J Clin Cases. 2019 Jul 26;7(14):1892-1898

Authors: Wang FF, Liu YS, Zhu WB, Liu YD, Chen Y

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disease of unknown aetiology. While it may affect any organ of the body, few cases of solitary lung involvement are published in the literature. Here, we report a rare case of pulmonary LCH (PLCH) in an adult.
CASE SUMMARY: A 52-year-old male presented to hospital in July 2018 with complaints of progressively worsening cough with sputum, breathlessness, easy fatigability, and loss of appetite since 2016, and a 32-year history of heavy cigarette smoking (average 30 cigarettes/d). Physical examination showed only weakened breathing sounds and wheezing during lung auscultation. Chest computed tomography (CT) showed irregular micronodules and multiple thin-walled small holes. Respiratory function tests showed a slight decrease. Ultrasonic cardiogram showed mild tricuspid regurgitation and no pulmonary hypertension. Fibreoptic bronchoscopy was performed with transbronchial biopsies from the basal segment of right lower lobe. LCH was confirmed by immunohistochemistry. The final diagnosis was PLCH without extra-pulmonary involvement. We suggested smoking cessation treatment. A 3-mo follow-up chest CT scan showed clear absorption of the nodule and thin-walled small holes. The symptoms of cough and phlegm had improved markedly and appetite had improved. There was no obvious dyspnoea.
CONCLUSION: Imaging manifestations of nodules, cavitating nodules, and thick-walled or thin-walled cysts prompted suspicion of PLCH and lung biopsy for diagnosis.

PMID: 31417936 [PubMed]

Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic Related Articles

[Durable remission of Langerhans cell sarcoma attained by autologous hematopoietic stem cell transplantation following surgical resection].

Rinsho Ketsueki. 2019;60(4):314-318

Authors: Fuseya H, Nakao T, Tsutsumi M, Nakaya Y, Horiuchi M, Yoshida M, Yoshimura T, Hayashi Y, Fukushima H, Inoue T, Aiba T, Yamane T

Langerhans cell sarcoma (LCS) is a rare neoplastic proliferation of Langerhans cells with a poor prognosis. Owing to its rarity, standard treatment for LCS has not been established to date. Here, we report a case of LCS occurring in multiple lymph nodes in the right cervix in which remission is maintained by autologous hematopoietic stem cell transplantation (auto-HSCT) after surgical resection. A 58-year-old male presented with enlarged right submandibular lymph nodes. Positron-emission tomography/computed tomography (PET/CT) revealed multiple lymphadenopathies in his right cervix. We performed a lymph node biopsy, and he was diagnosed with LCS. We selected the CHOP regimen as the first-line chemotherapy; however, rapid disease progression was observed soon after the first cycle of the therapy. The neck dissection was performed on day 16 of the CHOP therapy. As the residual tumor was suspected, we started the second-line chemotherapy with a combination of etoposide, cisplatin, ifosfamide, and gemcitabine; complete remission was confirmed by PET/CT. Subsequently, the patient was administered high-dose chemotherapy with auto-HSCT. After 2 years of auto-HSCT, complete remission has been maintained. Although there is no report of auto-HSCT for LCS, it could be an effective therapeutic tool for the disease.

PMID: 31068562 [PubMed - indexed for MEDLINE]

Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic Related Articles

[Fatal exacerbations of chronic active Epstein-Barr virus infection subsequent to cytotoxic chemotherapy].

Rinsho Ketsueki. 2019;60(4):286-290

Authors: Suma S, Kurita N, Baba N, Ishitsuka K, Sukegawa S, Makishima K, Kiyoki Y, Maruyama Y, Kato T, Yokoyama Y, Sakata-Yanagimoto M, Obara N, Hasegawa Y, Chiba S

Chronic active Epstein-Barr virus infection (CAEBV) is critical owing to lethal complications such as hemophagocytic lymphohistiocytosis (HLH), multiple organ failure, and malignant lymphoma. Here we present two cases of CAEBV who developed rapid and life-threatening disease progression after cytotoxic chemotherapy. Case 1: In a 34-year-old male, CAEBV recurred after 4-month remission obtained by initial therapy with etoposide, cyclosporine, and prednisolone. Accordingly, cord blood transplantation was planned. A day after administering high-dose melphalan as the conditioning, he developed respiratory failure, pancytopenia, and hyperferritinemia. He died 3 days later. Case 2: A 53-year-old female attained remission after initial therapy for CAEBV. After 1 month, she relapsed, and high-dose cytarabine (HDAC) was administered. A day after HDAC administration, she suddenly developed respiratory failure, which was followed by multiple organ failure. She died 3 days later. Thus, planned strategy for prompt allogeneic hematopoietic stem cell transplantation is necessary to prevent disease progression and control cytokinemia before cytotoxic chemotherapy for CAEBV.

PMID: 31068557 [PubMed - indexed for MEDLINE]

Icon for Ediciones Doyma, S.L. Related Articles

Intervertebral vacuum phenomenon: A cause of bulging of the pharyngeal wall.

Acta Otorrinolaringol Esp. 2018 Nov - Dec;69(6):370-371

Authors: Gorospe L, Gómez-García RM, Martínez San Millán J

PMID: 29625725 [PubMed - indexed for MEDLINE]

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