• Langerhans cells are dendritic cells found in the skin and function by internalizing antigens (foreign particles) and presenting them to T cells. (wikipedia.org)
  • Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the presence of cells with characteristics similar to bone marrow-derived Langerhans cells juxtaposed against a backdrop of hematopoietic cells, including T-cells, macrophages, and eosinophils. (medscape.com)
  • In 1868, Paul Langerhans discovered the epidermal dendritic cells that now bear his name. (medscape.com)
  • The ultrastructural hallmark of the Langerhans cell, the Birbeck granule, was described a century later. (medscape.com)
  • The term Langerhans cell histiocytosis is generally preferred to the older term, histiocytosis X. This newer name emphasizes the histogenesis of the condition by specifying the type of lesional cell and removes the connotation of the unknown ("X") because its cellular basis has now been clarified. (medscape.com)
  • Although the epidermal Langerhans cell has been presumed to be the cell of origin in LCH, recent studies have called this belief into question. (medscape.com)
  • Specifically, a variety of other cellular populations have been identified that possess phenotypic characteristics similar to Langerhans cells, including expression of CD207 and Birbeck granules. (medscape.com)
  • Therefore, in addition to epidermal Langerhans cells, other potential cellular origins for LCH include dermal langerin + dendritic cells, lymphoid tissue-resident langerin + dendritic cells, and monocytes that can be induced by local environmental stimuli to acquire a Langerhans cell phenotype. (medscape.com)
  • Notably, LCH cells have been found to express markers of both resting epidermal Langerhans cells (CD1a, intracellular major histocompatibility complex II [MHCII], Birbeck granules) and activated Langerhans cells (including CD54 and CD58). (medscape.com)
  • As a result, the pathologic cells of LCH have been hypothesized to represent Langerhans cells in a state of arrested maturation. (medscape.com)
  • [ 3 ] Taken together, these findings have led some to speculate that LCH is not a specific disease of epidermal Langerhans cells, but rather one of mononuclear phagocyte dysregulation. (medscape.com)
  • More recently, histiocytic diseases have been reclassified into five groups: (1) Langerhans-related, (2) cutaneous and mucocutaneous, (3) malignant histiocytosis, (4) Rosai-Dorfman disease, and (5) hemophagocytic lymphohistiocytosis and macrophage activation syndrome. (medscape.com)
  • The pathogenesis of Langerhans cell histiocytosis (LCH) is unknown. (medscape.com)
  • Broadly speaking, they can be divided into Langerhans and non-Langerhans cell histiocytoses. (thedoctorsdoctor.com)
  • Langerhans cell histiocytoses are all defined by the presence of a unique ultrastructural organelle, the Birbeck granule. (thedoctorsdoctor.com)
  • Currently, the preferred term is Langerhans cell histiocytosis. (thedoctorsdoctor.com)
  • Langerhans cell histiocytosis presenting in the neonatal period: a retrospective case series. (thedoctorsdoctor.com)
  • OBJECTIVES: To describe the morphologic characteristics of skin lesions, extent of extracutaneous disease, and outcomes in patients with neonatal presentation of Langerhans cell histiocytosis (LCH), and to examine clinical predictors of disease prognosis. (thedoctorsdoctor.com)
  • Epidemiologic study of Langerhans cell histiocytosis in children. (thedoctorsdoctor.com)
  • OBJECTIVE: The etiology and pathogenesis of Langerhans cell histiocytosis (LCH) remain poorly understood. (thedoctorsdoctor.com)
  • Genotyping of 69 histiocytic lesions revealed that 23/48 Langerhans cell lesions were BRAF -V600E-mutant whereas all non-Langerhans cell lesions (including dendritic cell sarcoma, juvenile xanthogranuloma, Rosai-Dorfman disease, and granular cell tumor) were wild-type. (oncotarget.com)
  • In conclusion, BRAF mutations in histiocytic proliferations are restricted to lesions of the Langerhans-cell type. (oncotarget.com)
  • Langerhans cell histiocytosis (LCH) is a proliferation of dendritic mononuclear cells with infiltration into organs locally or diffusely. (msdmanuals.com)
  • Гістіоцитоз легеневих клітин Лангерганса Pulmonary Langerhans cell histiocytosis (PLCH) is proliferation of monoclonal Langerhans cells in lung interstitium and airspaces. (msdmanuals.com)
  • Langerhans cell histiocytosis (LCH) is a dendritic cell (antigen-presenting cell) disorder. (msdmanuals.com)
  • Symptoms and signs of Langerhans cell histiocytosis vary considerably depending on which organs are infiltrated. (msdmanuals.com)
  • A 2010 study comparing gene expression of cells expressing CD207 (a marker of Langerhans cells) in LCH lesions with epidermal CD207+ control cells identified differential expression of more than 2000 genes between these 2 subsets. (medscape.com)
  • Langerhans cell histiocytosis is an expression of myeloid dendritic cells, associated with a significant inflammatory component and varied systemic involvement. (bvsalud.org)
  • Erdheim-Chester disease (ECD) is a rare and probably fatal multisystemic non-Langerhans cell histiocytosis (LCH). (bvsalud.org)
  • Langerhans cell histiocytosis (LCH) is a rare haematological neoplasm characterized by the accumulation of CD1a + , CD207/Langerin + histiocytes within inflammatory lesions. (biomedcentral.com)
  • Arguments supporting the reactive nature of LCH include the occurrence of spontaneous remissions, the extensive elaboration of multiple cytokines by dendritic cells and T-cells (the so-called cytokine storm) in LCH lesions, and the good survival rate in patients without organ dysfunction. (medscape.com)
  • The clinical manifestations of the currently recognized disease entities are highly variable and range from benign localized lesions to highly aggressive systemic diseases[ 4 ]. (oncotarget.com)
  • Pediatricians should pay much more attention to the cutaneous lesions in the neonatal period especially if there is any risk factor for presenting LCH such as IVF. (bvsalud.org)
  • These differences were found in genes involved in cell cycle regulation, apoptosis, cell signaling, metastasis, and myeloid differentiation. (medscape.com)
  • These neoplastic cells are the result of sporadic activating mutations in genes of the mitogen-activated protein kinase (MAPK) signaling pathway expressed by multipotent hematopoietic stem/progenitor cells or committed myeloid precursors [ 1 ]. (biomedcentral.com)
  • Using a more sensitive technique for detection of mutant BRAF alleles (droplet digital PCR) [ 9 ], BRAF V600E was not detected in DNA extracted from myeloid or lymphoid cells isolated by flowcytometric sorting from a peripheral blood sample collected at the time of the fourth bone sample. (biomedcentral.com)
  • Malignant histiocytosis is a rare hereditary disease found in the Bernese Mountain Dog and humans, characterized by histiocytic infiltration of the lungs and lymph nodes. (wikipedia.org)
  • better source needed] Other breeds with a possible genetic tendency toward malignant histiocytosis include Rottweilers, Flat-Coated Retrievers, and Golden Retrievers. (wikipedia.org)
  • Genetics of Malignant Histiocytosis in the Bernese Mountain Dog. (wikipedia.org)
  • The working group of the Histiocyte Society divided histocytic disorders into three groups: (1) dendritic cell histiocytosis, (2) macrophage-related disorders, and (3) malignant histiocytosis. (medscape.com)
  • A group of heterogeneous lymphoid tumors generally expressing one or more B-cell antigens or representing malignant transformations of B-lymphocytes. (lookformedical.com)
  • Any of a group of malignant tumors of lymphoid tissue that differ from HODGKIN DISEASE, being more heterogeneous with respect to malignant cell lineage, clinical course, prognosis, and therapy. (lookformedical.com)
  • Malignant lymphoma composed of large B lymphoid cells whose nuclear size can exceed normal macrophage nuclei, or more than twice the size of a normal lymphocyte. (lookformedical.com)
  • Malignant lymphoma in which the lymphomatous cells are clustered into identifiable nodules within the LYMPH NODES. (lookformedical.com)
  • and all cases showed typical morphology of Kikuchi disease, with necrosis, karyorrhectic debris, and the presence of the typical cell types, namely crescentic histiocytes and plasmacytoid monocytes. (medscape.com)
  • Lymphoma b cell. (lookformedical.com)
  • B-cell antigens are expressed on the immature cells that make up the tumor in virtually all cases of Burkitt lymphoma. (lookformedical.com)
  • A form of non-Hodgkin lymphoma having a usually diffuse pattern with both small and medium lymphocytes and small cleaved cells. (lookformedical.com)
  • Histopathological analysis of a thick needle biopsy demonstrated, however, a dense infiltrate of S100, CD1a and CD207/Langerin positive histiocytes accompanied by many eosinophilic granulocytes (Fig. 2 A), compatible with a diagnosis of LCH. (biomedcentral.com)
  • Histiocytic disorders refer to diseases that are caused by abnormal behavior of these cells. (wikipedia.org)
  • Histiocytic tumors are derived from the mononuclear-phagocytic and histiocyte system[ 1 - 3 ]. (oncotarget.com)
  • PATIENTS: Nineteen children with cutaneous findings in the first 4 weeks of life and subsequently diagnosed with LCH based on compatible tissue histologic analysis, confirmed by electron microscopy and/or immunohistochemical analysis. (thedoctorsdoctor.com)
  • MAIN OUTCOME MEASURE: Cutaneous lesion morphologic characteristics, extracutaneous manifestations, treatments, and outcomes were tabulated and compared. (thedoctorsdoctor.com)
  • The term "oncotarget" encompasses all molecules, pathways, cellular functions, cell types, and even tissues that can be viewed as targets relevant to cancer as well as other diseases. (oncotarget.com)
  • A general term for various neoplastic diseases of the lymphoid tissue. (lookformedical.com)
  • The only common feature among these tumors is the absence of giant REED-STERNBERG CELLS, a characteristic of Hodgkin's disease. (lookformedical.com)
  • B-cell lymphoid tumors that occur in association with AIDS. (lookformedical.com)
  • 1] This article focuses on cutaneous paraneoplastic syndromes caused by solid tumors. (medscape.com)
  • The most common clinical manifestation of Kikuchi disease is cervical lymphadenopathy, with or without systemic signs and symptoms. (medscape.com)
  • 10] Interestingly, this analysis found no differences in expression of proliferation markers between these subsets of CD207+ cells, consistent with the hypothesis that LCH may be a disease of abnormal cellular accumulation. (medscape.com)
  • On the other hand, the infiltration of organs by a monoclonal population of aberrant cells, the possibility of lethal evolution, and the cancer-based modalities of successful treatment are all consistent with a neoplastic process. (medscape.com)
  • A histiocyte is a differentiated tissue cell that has its origin in the bone marrow. (wikipedia.org)
  • Genotyping identified a 45 year-old woman with an aggressive and treatment-refractory, ultrastructurally confirmed systemic BRAF -mutant LCH. (oncotarget.com)
  • The majority of mantle-cell lymphomas are associated with a t(11;14) translocation resulting in overexpression of the CYCLIN D1 gene (GENES, BCL-1). (lookformedical.com)
  • Histopathology of peripheral nerve and sympathetic ganglion from a patient with autonomic failure, oat-cell carcinoma of the lung, and positive anti-HU antibody titer. (medscape.com)
  • Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. (lookformedical.com)
  • One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). (lookformedical.com)
  • A classification of B-lymphocytes based on structurally or functionally different populations of cells. (lookformedical.com)
  • A wide range of cutaneous signs may be related to internal malignancy. (medscape.com)
  • Histiocytes are a component of the immune system that proliferate abnormally in this disease. (wikipedia.org)
  • STUDY DESIGN: We used a case-control study design to obtain data from parents of children with LCH (n = 459) who were members of the Histiocytosis Association of America and Canada. (thedoctorsdoctor.com)
  • It is likely that polyclonal B-cell lymphoproliferation in AIDS is a complex result of EBV infection, HIV antigenic stimulation, and T-cell-dependent HIV activation. (lookformedical.com)