Langerhans cell histiocytosis is a disorder in which excess immune system cells called Langerhans cells build up in the body. Langerhans cells, which help regulate the immune system, are normally found throughout the body, especially in the skin , lymph nodes, spleen , lungs, liver , and bone marrow. In Langerhans cell histiocytosis , excess immature Langerhans cells usually form tumors called granulomas. Many researchers now consider Langerhans cell histiocytosis to be a form of cancer, but this classification remains controversial. In approximately 80 percent of affected individuals, one or more granulomas develop in the bones, causing pain and swelling. The granulomas, which usually occur in the skull or the long bones of the arms or legs, may cause the bone to fracture.
|Published (Last):||11 July 2012|
|PDF File Size:||3.73 Mb|
|ePub File Size:||12.9 Mb|
|Price:||Free* [*Free Regsitration Required]|
Langerhans cell histiocytosis is a disorder in which excess immune system cells called Langerhans cells build up in the body. Langerhans cells, which help regulate the immune system, are normally found throughout the body, especially in the skin , lymph nodes, spleen , lungs, liver , and bone marrow.
In Langerhans cell histiocytosis , excess immature Langerhans cells usually form tumors called granulomas. Many researchers now consider Langerhans cell histiocytosis to be a form of cancer, but this classification remains controversial. In approximately 80 percent of affected individuals, one or more granulomas develop in the bones, causing pain and swelling. The granulomas, which usually occur in the skull or the long bones of the arms or legs, may cause the bone to fracture.
Granulomas also frequently occur in the skin, appearing as blisters, reddish bumps, or rashes which can be mild to severe. The pituitary gland may also be affected; this gland is located at the base of the brain and produces hormones that control many important body functions. Without hormone supplementation, affected individuals may experience delayed or absent puberty or an inability to have children infertility.
In addition, pituitary gland damage may result in the production of excessive amounts of urine diabetes insipidus and dysfunction of another gland called the thyroid. Thyroid dysfunction can affect the rate of chemical reactions in the body metabolism , body temperature, skin and hair texture, and behavior. In 15 to 20 percent of cases, Langerhans cell histiocytosis affects the lungs, liver, or blood-forming hematopoietic system; damage to these organs and tissues may be life-threatening.
Lung involvement , which appears as swelling of the small airways bronchioles and blood vessels of the lungs, results in stiffening of the lung tissue, breathing problems, and increased risk of infection. Hematopoietic involvement, which occurs when the Langerhans cells crowd out blood-forming cells in the bone marrow , leads to a general reduction in the number of blood cells pancytopenia.
Pancytopenia results in fatigue due to low numbers of red blood cells anemia , frequent infections due to low numbers of white blood cells neutropenia , and clotting problems due to low numbers of platelets thrombocytopenia. Other signs and symptoms that may occur in Langerhans cell histiocytosis , depending on which organs and tissues have Langerhans cell deposits, include swollen lymph nodes, abdominal pain, yellowing of the skin and whites of the eyes jaundice , delayed puberty, protruding eyes, dizziness, irritability, and seizures.
About 1 in 50 affected individuals experience deterioration of neurological function neurodegeneration. Langerhans cell histiocytosis is often diagnosed in childhood, usually between ages 2 and 3, but can appear at any age. Most individuals with adult-onset Langerhans cell histiocytosis are current or past smokers; in about two-thirds of adult-onset cases the disorder affects only the lungs.
The severity of Langerhans cell histiocytosis , and its signs and symptoms, vary widely among affected individuals. Certain presentations or forms of the disorder were formerly considered to be separate diseases. In many people with Langerhans cell histiocytosis , the disorder eventually goes away with appropriate treatment.
It may even disappear on its own, especially if the disease occurs only in the skin. However, some complications of the condition, such as diabetes insipidus or other effects of tissue and organ damage, may be permanent. Langerhans cell histiocytosis is a rare disorder. Its prevalence is estimated at 1 to 2 in , people. Somatic mutations in the BRAF gene have been identified in the Langerhans cells of about half of individuals with Langerhans cell histiocytosis.
Somatic gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes are not inherited. The BRAF gene provides instructions for making a protein that is normally switched on and off in response to signals that control cell growth and development.
Somatic mutations cause the BRAF protein in affected cells to be continuously active and to transmit messages to the nucleus even in the absence of these chemical signals. The overactive protein may contribute to the development of Langerhans cell histiocytosis by allowing the Langerhans cells to grow and divide uncontrollably.
Changes in other genes have also been identified in the Langerhans cells of some individuals with Langerhans cell histiocytosis. Some researchers believe that additional factors, such as viral infections and environmental toxins, may also influence the development of this complex disorder. Langerhans cell histiocytosis is usually not inherited and typically occurs in people with no history of the disorder in their family. A few families with multiple cases of Langerhans cell histiocytosis have been identified, but the inheritance pattern is unknown.
Biological and clinical significance of somatic mutations in Langerhans cell histiocytosis and related histiocytic neoplastic disorders. Cell s of Origin of Langerhans Cell Histiocytosis.
Hematol Oncol Clin North Am. Epub Aug Langerhans cell histiocytosis is a neoplasm and consequently its recurrence is a relapse: In memory of Bob Arceci. Pediatr Blood Cancer. Epub Jun Langerhans cell histiocytosis: a comprehensive review. Harmon CM, Brown N. Arch Pathol Lab Med.
Monsereenusorn C, Rodriguez-Galindo C. Genes Chromosomes Cancer. Epub Mar BRAF VE expression in Langerhans cell histiocytosis: clinical and immunohistochemical study on 25 pulmonary and 54 extrapulmonary cases. Am J Surg Pathol. Rollins BJ. Genomic Alterations in Langerhans Cell Histiocytosis. Oncology Williston Park.
Non-Langerhans cell histiocytosis
DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages. Non-Langerhans cell histiocytosis has this name to differentiate it from Langerhans cell histiocytosis. 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 histiocytosis involves dermal dendritic cells.
Langerhans cell histiocytosis
It seeks to promote medical-scientific writing and thereby support research and creativity in Medicine. The journal aims as well to support the medical-biological sciences related to health as to have a space for history, philosophy and ethics. Medical writing without relation to science is promoted: anecdotes, stories and short stories of doctors and patients. Langerhans cell Histiocytosis LCH is a rare disease characterized by the neoplastic proliferation of Langer-hans-type cells that express CD1a, langerin and S protein with variable number of eosinophils, neutrophils and small lymphocytes. An optimal treatment regimen that could lead to a lasting remission or cure is not defined yet but etoposide and vinblastine are considered to be the most effective agents as monochemotherapy. Systemic treatments for refractory LCH have been unsatisfactory and usually toxic, 2 however; Saven and Burian demonstrated that cladribine has major activity in these patients.