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Blood Apr 2020Langerhans cell histiocytosis (LCH) is caused by clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in lesions that leads to a spectrum of... (Review)
Review
Langerhans cell histiocytosis (LCH) is caused by clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in lesions that leads to a spectrum of organ involvement and dysfunction. The pathogenic cells are defined by constitutive activation of the MAPK signaling pathway. Treatment of LCH is risk-adapted: patients with single lesions may respond well to local treatment, whereas patients with multisystem disease require systemic therapy. Although survival rates for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 20%. Despite progress made in the treatment of LCH, disease reactivation rates remain above 30%, and standard second-line treatment is yet to be established. Treatment failure is associated with increased risks for death and long-term morbidity, including LCH-associated neurodegeneration. Early case series report promising clinical responses in patients with relapsed and refractory LCH treated with BRAF or MEK inhibitors, although potential for this strategy to achieve cure remains uncertain.
Topics: Animals; Histiocytosis, Langerhans-Cell; Humans; MAP Kinase Signaling System; Mutation; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf
PubMed: 32106306
DOI: 10.1182/blood.2019000934 -
The Veterinary Clinics of North... Jan 2023Canine cutaneous histiocytomas originate from Langerhans cells. Multiple histiocytomas are referred to as cutaneous Langerhans cell histiocytosis. Feline pulmonary... (Review)
Review
Canine cutaneous histiocytomas originate from Langerhans cells. Multiple histiocytomas are referred to as cutaneous Langerhans cell histiocytosis. Feline pulmonary Langerhans cell histiocytosis causes respiratory failure owing to extensive lung infiltration. Localized and disseminated histiocytic sarcomas usually arise from interstitial dendritic cells. Primary sites include spleen, lung, skin, brain (meninges), lymph node, bone marrow, and synovial tissues of limbs. An initially indolent form of localized histiocytic sarcomas, progressive histiocytosis, originates in the skin of cats. Hemophagocytic histiocytic sarcomas originates in splenic red pulp macrophages. Canine reactive histiocytoses (systemic histiocytosis and cutaneous histiocytosis) are complex inflammatory diseases with underlying immune dysregulation.
Topics: Dogs; Cats; Animals; Histiocytic Sarcoma; Dog Diseases; Histiocytosis, Langerhans-Cell; Skin; Skin Neoplasms; Cat Diseases
PubMed: 36270835
DOI: 10.1016/j.cvsm.2022.07.010 -
Medicina Clinica Aug 2023Histiocytosis is a group of rare diseases characterized by inflammation and accumulation of cells derived from monocytes and macrophages in different tissues. The... (Review)
Review
Histiocytosis is a group of rare diseases characterized by inflammation and accumulation of cells derived from monocytes and macrophages in different tissues. The symptoms are highly variable, from mild forms with involvement of a single organ to severe multisystem forms that can be life compromising. The diagnosis of histiocytosis is based on the clinic, radiological findings and pathological anatomy. A biopsy of the affected tissue is recommended in all cases as it may have therapeutic implications. During the last decade, some mutations have been identified in the affected tissue that condition activation of the MAPK/ERK and PI3K/AKT pathway, in a variable proportion depending on the type of histiocytosis. In this review we mainly focus on Langerhans Cell Histiocytosis, Erdheim-Chester Disease and Rosai-Dorfman Disease.
Topics: Humans; Phosphatidylinositol 3-Kinases; Histiocytosis, Langerhans-Cell; Erdheim-Chester Disease; Histiocytosis, Sinus; Mutation
PubMed: 37263840
DOI: 10.1016/j.medcli.2023.05.001 -
Histopathology Jan 2022Cutaneous histiocytoses constitute a heterogeneous group of diseases characterised by the cutaneous accumulation of cells with the cytological and phenotypic features of... (Review)
Review
Cutaneous histiocytoses constitute a heterogeneous group of diseases characterised by the cutaneous accumulation of cells with the cytological and phenotypic features of macrophages or dendritic cells. The clinical spectrum ranges from self-resolving, skin-limited conditions to severe, multiorgan disease with a high morbidity rate. Until recently, cutaneous histiocytoses were classified according to the immunophenotype of the pathological cells, with differentiation between Langerhans cell histiocytosis (LCH) [CD1a+, CD207 (langerin)+] and non-Langerhans cell histiocytosis (CD68+, CD163+, CD1a-, CD207-). Over the last 12 years, a number of new pathophysiological findings (in particular, molecular pathology results) regarding histiocytoses have contributed to a new classification based on molecular alterations, as well as on clinical and imaging characteristics and the phenotype. The most frequent entities in children are juvenile xanthogranuloma and LCH.
Topics: Child; Disease Progression; Histiocytosis; Histiocytosis, Langerhans-Cell; Humans; Skin; Xanthogranuloma, Juvenile
PubMed: 34958507
DOI: 10.1111/his.14569 -
Hematological Oncology Jun 2021Children with Langerhnans cell histiocytosis (LCH) develop granulomatous lesions with characteristic clonal CD207+ dendritic cells that can arise as single lesions or... (Review)
Review
Children with Langerhnans cell histiocytosis (LCH) develop granulomatous lesions with characteristic clonal CD207+ dendritic cells that can arise as single lesions or life-threatening disseminated disease. Despite the wide range of clinical presentations, LCH lesions are histologically indistinguishable based on severity of disease, and uncertain classification as an immune versus neoplastic disorder has historically challenged the development of optimal clinical strategies for patients with LCH. Recently, activating somatic mutations in MAPK pathway genes, most notably BRAFV600E, have been discovered in almost all cases of LCH. Further, the stage of myeloid differentiation in which the mutation arises defines the extent of disease and risk of developing LCH-associated neurodegeneration. MAPK activation in LCH precursor cells drives myeloid differentiation, inhibits migration, and inhibits apoptosis, resulting in accumulation of resilient pathologic dendritic cells that recruit and activate T cells. Recurrent somatic mutations in MAPK pathway genes have also been identified in related histiocytic disorders: juvenile xanthogranuloma, Erdheim-Chester disease, and Rosai-Dorfman disease. New insights into pathogenesis support reclassification of these conditions as a myeloid neoplastic disorders. Continued research will uncover opportunities to identify novel targets and inform personalized therapeutic strategies based on cell of origin, somatic mutation, inherited risk factors, and residual disease.
Topics: Amino Acid Substitution; Cell Differentiation; Cell Movement; Dendritic Cells; Histiocytosis, Langerhans-Cell; Humans; MAP Kinase Signaling System; Mutation, Missense; Precision Medicine; Proto-Oncogene Proteins B-raf; T-Lymphocytes
PubMed: 34105821
DOI: 10.1002/hon.2857 -
Radiologia Dec 2022The term cystic lung disease encompasses a heterogeneous group of entities characterised by round lung lesions that correspond to cysts with fine walls, which usually...
The term cystic lung disease encompasses a heterogeneous group of entities characterised by round lung lesions that correspond to cysts with fine walls, which usually contain air. The differential diagnosis of these lesions can be challenging, requiring both clinical and radiological perspectives. Entities such as pulmonary emphysema and cystic bronchiectasis can simulate cystic disease. High-resolution computed tomography (HRCT) is the imaging technique of choice for the evaluation and diagnosis of cystic lung disease, because it confirms the presence of lung disease and establishes the correct diagnosis of the associated complications. In many cases, the diagnosis can be established based on the HRCT findings, thus making histologic confirmation unnecessary. For these reasons, radiologists need to be familiar with the different presentations of these entities. A wide variety of diseases are characterised by the presence of diffuse pulmonary cysts. Among these, the most common are lymphangioleiomyomatosis, which may or may not be associated with tuberous sclerosis, Langerhans cell histiocytosis, and lymphocytic interstitial pneumonia. Other, less common entities include Birt-Hogg-Dubé syndrome, amyloidosis, and light-chain deposit disease. This article describes the characteristics and presentations of some of these entities, emphasizing the details that can help differentiate among them.
Topics: Humans; Lung Diseases, Interstitial; Lung; Lymphangioleiomyomatosis; Histiocytosis, Langerhans-Cell; Cysts
PubMed: 36737165
DOI: 10.1016/j.rxeng.2022.09.005 -
Blood Apr 2022Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal,...
Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.
Topics: Adult; Child; Cladribine; Consensus; Histiocytosis, Langerhans-Cell; Humans; MAP Kinase Signaling System; Mutation
PubMed: 35271698
DOI: 10.1182/blood.2021014343 -
Neuro-oncology Sep 2021Histiocytoses are heterogeneous hematopoietic diseases characterized by the accumulation of CD68(+) cells with various admixed inflammatory infiltrates. The... (Review)
Review
Histiocytoses are heterogeneous hematopoietic diseases characterized by the accumulation of CD68(+) cells with various admixed inflammatory infiltrates. The identification of the pivotal role of the mitogen-activated protein kinase (MAPK) pathway has opened new avenues of research and therapeutic approaches. We review the neurologic manifestations of 3 histiocytic disorders with frequent involvement of the brain and spine: Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and Rosai-Dorfman-Destombes disease (RDD). Central nervous system (CNS) manifestations occur in 10%-25% of LCH cases, with both tumorous or neurodegenerative forms. These subtypes differ by clinical and radiological presentation, pathogenesis, and prognosis. Tumorous or degenerative neurologic involvement occurs in 30%-40% of ECD patients and affects the hypothalamic-pituitary axis, meninges, and brain parenchyma. RDD lesions are typically tumorous with meningeal or parenchymal masses with strong contrast enhancement. Unlike LCH and ECD, neurodegenerative lesions or syndromes have not been described with RDD. Familiarity with principles of evaluation and treatment both shared among and distinct to each of these 3 diseases is critical for effective management. Refractory or disabling neurohistiocytic involvement should prompt the consideration for use of targeted kinase inhibitor therapies.
Topics: Central Nervous System; Erdheim-Chester Disease; Histiocytosis, Langerhans-Cell; Histiocytosis, Sinus; Humans; Prognosis
PubMed: 33993305
DOI: 10.1093/neuonc/noab107 -
Best Practice & Research. Clinical... Sep 2020Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a... (Review)
Review
Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of conditions (genetic, congenital, inflammatory, neoplastic, traumatic) that arise mainly from the hypothalamus. The differential diagnosis between diseases presenting with polyuria and polydipsia is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating the sellar-suprasellar region in CDI. Pituitary stalk size at presentation is variable and can change over time, depending on the underlying condition, and other brain areas or other organs - in specific diseases - may become involved during follow up. An early diagnosis and treatment are preferable in order to avoid central nervous system damage and the risk of dissemination of germ cell tumor, or progression of Langerhans Cell Histiocytosis, and in order to start treatment of additional pituitary defects without further delay. This review focuses on current diagnostic work-up and on the role of neuroimaging in the differential diagnosis of CDI in children and adolescents. It provides an update on the best approach for diagnosis - including novel biochemical markers such as copeptin - treatment and follow up of children and adolescents with CDI; it also describes the best approach to challenging situations such as post-surgical patients, adipsic patients, patients undergoing chemotherapy and/or in critical care.
Topics: Adolescent; Age of Onset; Biomarkers; Brain; Child; Diabetes Insipidus, Neurogenic; Diagnosis, Differential; Diagnostic Imaging; Diagnostic Techniques, Endocrine; Histiocytosis, Langerhans-Cell; Humans; Magnetic Resonance Imaging; Polydipsia; Polyuria
PubMed: 32646670
DOI: 10.1016/j.beem.2020.101440 -
Clinical Lymphoma, Myeloma & Leukemia Jan 2021Histiocytic disorders are an exceptionally rare group of diseases with diverse manifestations and a paucity of approved treatments, thereby leading to various challenges... (Review)
Review
Highlights of the Management of Adult Histiocytic Disorders: Langerhans Cell Histiocytosis, Erdheim-Chester Disease, Rosai-Dorfman Disease, and Hemophagocytic Lymphohistiocytosis.
Histiocytic disorders are an exceptionally rare group of diseases with diverse manifestations and a paucity of approved treatments, thereby leading to various challenges in their diagnosis and management. With the discovery of novel molecular targets and the incorporation of targeted agents in the management of various adult histiocytic disorders, their management has become increasingly complex. In an attempt to improve the understanding of the clinical features and management of common adult histiocytic disorders (Langerhans cell histiocytosis, Erdheim-Chester disease, Rosai-Dorfman disease, and hemophagocytic lymphohistiocytosis), we created this document based on existing literature and expert opinion.
Topics: Adult; Drug Therapy, Combination; Erdheim-Chester Disease; Histiocytosis, Langerhans-Cell; Histiocytosis, Sinus; Humans; Lymphohistiocytosis, Hemophagocytic; Treatment Outcome
PubMed: 32943371
DOI: 10.1016/j.clml.2020.08.007