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

Langerhans cells represent a minor epidermal cell population in mammals. They are also observed in squamous epithelia of the oesophagus, vagina and cervix, as well as in oral epithelia. They occur in higher density in the non keratinized epithelium. These cells are characterized by a dendritic pattern, a clear cytoplasm and ultrastructurally by the presence of Birbeck granules. They are usually located in a suprabasal position. Their bone marrow origin is now well established. Surface markers and functional properties identify them as belonging to the macrophage/monocyte lineage. Langerhans cells can be identified in tissue sections by immunofluorescence or immunoperoxidase techniques using monoclonal antibodies directed against surface antigens such as class II histocompatibility antigens, T6 marker, or possibly T4 marker. There is also a cytoplasmic marker, the S-100 protein. A renewed interest in Langerhans cells comes from evidence of their role in the cutaneous immune response. At present these cells are considered as dendritic cells expressing a high density of class II histocompatibility antigens and behave as very potent antigen presenting cells that activate mainly helper T lymphocytes. However, experimental data on antigen processing and interleukin 1 secretion are still lacking. This review also examines the oral pathology literature with respect to modifications in the number or localization of Langerhans cells and their proximity to T lymphocytes, for example in lichen planus, Behcet's syndrome, erythema multiforme, gingivitis and oral carcinoma. Histiocytosis X represents a particular case in which the Langerhans cell itself is affected.
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PMID:[Physiology of Langerhans cells and their potential role in oral pathology]. 351 86

We reviewed the Tumor Registry for 1981 at the Children's Hospital of Philadelphia to identify all the children with newly diagnosed cancer who were seen initially in the emergency department (ED). Of the 220 new patients listed, 16 (7.3%) sought initial care in the ED (1 per 4,500 ED visits). Seven had leukemia, five had non-CNS solid tumors (2 lymphoreticular, 1 Wilms', 1 neuroblastoma, and 1 ovarian), and four had CNS tumors. Among the children with leukemia, pallor (6) and decreased activity (4) were the most common complaints. Duration of symptoms ranged from 4 days to 3 weeks. Physical examination showed pallor (5), splenomegaly (4), fever (3), hepatomegaly (3), lymphadenopathy (3), and ecchymoses or petechiae (2). The complete blood count and peripheral smears were all abnormal. The five patients with non-CNS solid tumors had symptoms related to the location of their neoplasms. The patients with Wilms' tumor, neuroblastoma, and ovarian dysgerminoma had abdominal masses; the patient with lymphoma had a large, painful inguinal node; and the patient with histiocytosis X had an infiltrative rash, gingivitis, and pneumonitis. Of the four children with CNS tumors, three had headache, and one had an incidentally detected scotoma following head trauma. All four eventually had abnormal neurologic exams and computer tomographic scans, but two were discharged initially with psychiatric diagnoses. We conclude that cancer, although rare in children, occurs with greater relative frequency in the referral hospital ED than that predicted by published cancer rates from the referring hospital's ED.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Detection of cancer in the pediatric emergency department. 384 22

Langerhans' cell histiocytosis (LCH) is a rare paediatric disease of unknown etiology affecting 1 to 5 children per 1 million each year. It is characterized by the idiopathic proliferation of Langerhans' cells. The clinical spectrum of disease is quite varied, ranging from a solitary eosinophilic granuloma to diffuse multisystem involvement. The head and neck is the most common site of involvement, occurring in approximately 60% of LCH patients. Head and neck manifestations are diverse and include skull and temporal bone lesions, cervical lymphadenopathy, and skin rash. Diagnosis can be difficult as these lesions mimic other common conditions seen by the otolaryngologist, including otitis externa, acute mastoiditis, and gingivitis. A retrospective study was carried out to study our centre's experience with LCH over the last 10 years. Twenty-one patients were diagnosed between January 1990 and December 1999. Patient's age at time of diagnosis ranged from 6 days to 14 years. Fifty-seven percent of patients had localized bony lesions; the remaining 43% had diffuse multisystem disease. The head and neck was also the most commonly involved site in our study, affecting 67% of our patients. Presentation and diagnosis of these lesions are discussed in detail. Treatment, complications, and patient outcomes will also be discussed.
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PMID:Langerhans' cell histiocytosis in the paediatric population: presentation and treatment of head and neck manifestations. 1277 59