Histiocytosis
Histiocytosis refers to a group of rare blood disorders characterized by the abnormal accumulation of white blood cells known as histiocytes, which include monocytes and macrophages. The most common type is Langerhans cell histiocytosis (LCH), affecting approximately four to five individuals per million, with a higher prevalence in males. This condition can impact various organs such as the bones, skin, lungs, liver, and gastrointestinal system. Symptoms are diverse and depend on the severity of the condition, potentially including bone lesions, skin rashes, respiratory issues, and gastrointestinal bleeding.
LCH may arise as a response to immunodeficiency or as a secondary effect of viral infections. While some patients may experience minimal symptoms or localized disease, others might require more aggressive treatment, including chemotherapy. Diagnosis often necessitates a biopsy and may involve radiologic tests like chest x-rays or skeletal surveys due to the rarity of the disorder. The impacts of LCH can vary significantly, with potential long-term effects such as stunted growth and hearing loss, emphasizing the importance of comprehensive care from various medical professionals.
Histiocytosis
ALSO KNOWN AS: Langerhans cell histiocytosis (LCH), histiocytosis X, eosinophilic granuloma, Hand-Schüller-Christian disease, Letterer-Siwe disease
ANATOMY OR SYSTEM AFFECTED: Blood, bones, ears, gastrointestinal system, immune system, liver, lungs, nervous system, skin, throat
DEFINITION: A group of relatively rare blood disorders characterized by the abnormal accumulation of white blood cells called histiocytes leading to a wide range of adverse bodily responses
CAUSES: Response to underlying immunodeficiency or secondary effect from viral infection
SYMPTOMS: Depends on severity; may include bone lesions (especially skull), rashes, respiratory problems (cough, shortness of breath), gastrointestinal problems (bleeding, elevated liver enzymes)
DURATION: Short-term or long-term
TREATMENTS: Depends on the severity; may include chemotherapy
Causes and Symptoms
There is no clear understanding of the exact of histiocytoses, blood disorders characterized by an accumulation of white blood cells called histiocytes, including monocytes, and macrophages. Langerhans cell histiocytosis (LCH) is the most common type. At least four or five people per million are affected, with more males affected than females. The disorder affects both children and adults.
LCH may develop in response to underlying immunodeficiency or as a secondary effect from a viral infection. Symptoms vary based on the severity of the disease, and patients may be relatively symptom-free. LCH may be localized to one area or organ, or it may be more diffuse, involving multiple organs. It can cause lesions on bone, especially skull bones, or it may manifest itself as a skin rash. Respiratory symptoms such as cough or shortness of breath may signify that LCH has affected the lungs. Gastrointestinal manifestations of the disease include bleeding within the tract or elevated liver enzymes. LCH can also affect the lymph nodes or the and may contribute to the development of diabetes insipidus, growth hormone deficiency, and hypopituitarism (underactive pituitary gland).
Definitive diagnosis requires a biopsy, and the differential diagnosis (other diseases similar to it) is broad. Making the diagnosis requires a high index of suspicion because it is rare and easily missed. Helpful radiologic tests might include a chest x-ray or a skeletal survey.
Treatment and Therapy
Treatment options vary widely based on the severity of the disease. On one hand, minimal treatment may be needed for symptom-free, single-system involvement, especially as LCH affecting only one system often remits completely. On the other hand, more severe disease affecting many systems may warrant chemotherapy, with characteristic remissions and relapses.
Perspective and Prospects
The histiocytoses are classified into three types: LCH, hemophagocytic lymphohistiocytosis (HLH), and malignant histiocytosis. The impacts of LCH can be many, some with short-term and others with long-term consequences: stunted growth, dental problems, hearing loss, and fibrosis, to name a few. Though caregivers from a variety of medical specialties are often involved in caring for LCH patients and tremendous strides in diagnosis and treatment have been made, many patients still suffer from problematic, recurrent disease.
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