Histiocytosis | |
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Specialty | Hematology ![]() |
Inmedicine,histiocytosis is an excessive number ofhistiocytes[1] (tissuemacrophages), and the term is also often used to refer to a group of rare diseases which share thissign as a characteristic. Occasionally and confusingly, the termhistiocytosis is sometimes used to refer to individual diseases.
According to theHistiocytosis Association, 1 in 200,000 children in theUnited States are born with histiocytosis each year.[2] HAA also states that most of the people diagnosed with histiocytosis are children under the age of 10, although the disease can afflict adults. The disease usually occurs from birth to age 15.[3]
Histiocytosis (andmalignant histiocytosis) are both important in veterinary as well as human pathology.
Histiocytosis is a rare disease, thus its diagnosis may be challenging. A variety of tests may be used, including:[5]
There are competing systems for classifying histiocytoses. According to the 1999 classification proposed by theWorld Health Organization, they can be divided into three categories.[6][7] However, the classifications in ICD10 and MeSH are slightly different, as shown below:
Name | WHO | ICD10 | MeSH |
---|---|---|---|
Langerhans cell histiocytosis (LCH) | I | D76.0 | Langerhans-cell histiocytosis |
Juvenile xanthogranuloma (JXG) | II | D76.3 | non-Langerhans-cell histiocytosis |
Hemophagocytic lymphohistiocytosis (HLH) | II | D76.1 | non-Langerhans-cell histiocytosis |
Niemann–Pick disease | II | E75.2 | non-Langerhans-cell histiocytosis |
Sea-blue histiocytosis | II | – | non-Langerhans-cell histiocytosis |
Acute monocytic leukemia | III | C93.0 | malignant histiocytic disorders |
Malignant histiocytosis | III | C96.1 | malignant histiocytic disorders |
Erdheim–Chester disease | II | C96.1 | malignant histiocytic disorders |
Alternatively, histiocytoses may be divided into the following groups:[8]: 714–724
Lymphohistiocytosis is a similar immune system disease characterized by the inappropriate activation of natural killer cells, CD8+ cytotoxic T-cells, and macrophages, involving principally the liver, spleen and central nervous system and associated with severe lymphoid atrophy.[9][10]
Various treatments exist for histiocytosis. The one selected depends on the location of the disease and the patient history. The modalities used may include:[11]
Patients and families can gain support and educational materials from the Histiocytosis Association.[citation needed]
TheHistiocyte Society, a nonprofit organization, is a group of more than 200 physicians and scientists from around the world committed to improving the lives of patients with histiocytic disorders by conducting clinical and laboratory research into the causes and treatment of this disease. The Society has instituted several clinical trials and treatment plans.[12][13]
TheNorth American Consortium for Histiocytosis (NACHO) is a group of institutions that collaborate on scientific and clinical research for histiocytic diseases. Established in 2014 by 12 institutions, it was funded through a consortium grant from theSt. Baldrick's Foundation.[14]