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Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemophagocytic lymphohistiocytosis, terminology that designates a syndrome that may be familial or sporadic, with or without an associated viral infection, is presented as the prototype of a hemophagocytic syndrome, a condition in which there is uncontrolled activation of the cellular immune system. Diagnostic criteria include idiopathic fever, splenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, and the presence of hemophagocytosis. The surgical and autopsy pathology features infiltrates composed of lymphocytes and ordinary, but activated, histiocytes and hemophagocytosis. The chronic hepatitis-like hepatic lesion is noted to be characteristic, if not unique, in this age group and setting. Current concepts of pathophysiology focus on the role of cytokines, particularly interleukin (IL)-1, IL-2, soluble IL-2 receptor, plasminogen activator, and prostaglandins. The clinicopathologic features of the syndrome can be accounted for by the uncontrolled and unopposed production and release of these mediators. Nosology places hemophagocytic lymphohistiocytosis in the position of the most important of the "benign" histiocytosis syndromes that involve ordinary histiocytes of the mononuclear phagocytic system in contrast to Langerhans cell histiocytosis (histiocytosis X) in which pathological dendritic histiocytes are operative. Features that distinguish hemophagocytic lymphohistiocytosis from other disorders, such as malignant histiocytosis, X-linked lymphoproliferative disorder, congenital immunodeficiency states, the accelerated phase of Chediak-Higashi syndrome, and cytophagic histiocytic panniculitis, which may be associated with a hemophagocytic syndrome, are presented.
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PMID:Hemophagocytic lymphohistiocytosis: a hemophagocytic syndrome. 156 89

Familial hemophagocytic lymphohistiocytosis (FHL) is probably a genetically transmitted disease affecting infants and very young children. Cardinal symptoms are fever, hepatosplenomegaly, and pancytopenia. Frequently meningeal involvement is seen, manifested by neurologic symptoms and a lymphohistiocytic pleocytosis with increased protein levels in the cerebrospinal fluid. Characteristic laboratory findings in FHL are hypertriglyceridemia and hypofibrinogenemia, which are reversible with treatment. The disease has been rapidly fatal in most patients, but recently longterm remissions have been achieved with cytotoxic agents. Pathohistologic examination shows a widespread infiltrate of lymphocytes and mature macrophages with prominent hemophagocytosis affecting especially liver, spleen, lymph nodes and the central nervous system. Atrophy of the lymphatic tissue is a common finding. From the histologic picture FHL has to be grouped among the histiocytoses of reactive origin since the cells involved show no signs of malignancy. The etiology and pathogenesis of FHL are not known at present. Immunologic studies present evidence for a disturbed function of T lymphocytes, but a secondary immune defect seems to be more likely than primary immune deficiency. Among the broad clinical spectrum of histiocytic disorders especially histiocytic reactions due to infection, histiocytosis X and malignant histiocytosis have to be considered in the differential diagnosis of FHL.
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PMID:Familial hemophagocytic lymphohistiocytosis. 635 20

A case of a girl with Langerhans cell histiocytosis who had hypofibrinogenemia during etoposide (VP-16) and prednisolone therapy is described. A patient on a three times per week schedule of 100 mg/m2 etoposide in combination with 40 mg/m2 of prednisolone every day had hypofibrinogenemia of 90 mg/dL after 12 doses of etoposide. Hypofibrinogenemia improved after discontinuing the course of etoposide. The clinical course suggested that the combination of etoposide with prednisolone caused this side-effect. Although the exact mechanism of toxicity of etoposide with prednisolone remains unknown, it is possible that the side-effect might be due to reduced production of fibrinogen in the liver. Careful monitoring of fibrinogen is mandatory in patients receiving etoposide and prednisolone.
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PMID:Hypofibrinogenemia in a girl with Langerhans cell histiocytosis during etoposide and prednisolone therapy. 850 73

This study evaluates the clinical and laboratory data of children with secondary hemophagocytic lymphohistiocytosis (sHLH) related to malignancy. Charts of patients who met the diagnostic criteria for sHLH associated with malignancy between January 2000-2006 at six different hospitals in Turkey were reviewed retrospectively. The diagnosis of HLH had been established by bone marrow aspiration in 27 patients, cerebrospinal fluid and bone marrow aspiration in one patient and lung-liver biopsy in another. Twenty-nine children were diagnosed as having sHLH related to malignancy. Twenty cases (18 ALL and 2 AML) with acute leukemia (10 girls/10 boys, median age: 8 years [3-14 years]) were found to have sHLH. Five patients with acute leukemia had HLH at the time of diagnosis (Group 1a), and 15 patients with acute leukemia were diagnosed as having sHLH during therapy (Group 1b), namely reactive sHLH associated with the chemotherapy. Nine patients, including two cases each of rhabdomyosarcoma, neuroblastoma, Hodgkin disease, and non-Hodgkin lymphoma (NHL) and one case with Langerhans cell histiocytosis, were diagnosed as having concomitant hemophagocytosis at the initial evaluation of the tumor (Group 2). Fever, anemia, and hypertriglyceridemia were present in all sHLH cases of all three groups. Hepatomegaly was detected in 60.0%, 73.3%, and 88.8% of the three groups, respectively. Splenomegaly was more frequent in patients of Groups 1a (60.0%) and 2 (88.8%) than in those of Group 1b, the reactive ones (13.3%). Hypofibrinogenemia was detected in all patients of Group 1a and Group 2. Low level of fibrinogen was present in 91.6% of patients in Group 1b. All patients in Group 1b (100%) had neutropenia and thrombocytopenia. Neutropenia was found at rates of 60.0% and 55.5% in Group 1a and Group 2, respectively. Thrombocytopenia was detected in 80.0% of patients in Group 1a and 77.7% in Group 2. The overall mortality rate was 34.4% (10 cases) in our series of 29 children with sHLH; 50% of deaths were directly attributable to HLH. Pediatric malignancy-associated HLH patients have been commonly described as case presentations or in a review of the literature. We believe that our cohort, compiling 29 children regarding the association between malignancy and HLH, will be useful for pediatricians who are interested in this still mysterious topic.
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PMID:Malignancy-associated hemophagocytic lymphohistiocytosis in pediatric cases: a multicenter study from Turkey. 1981 62