Langerhans cell histiocytosis and other disorders of monocyte-histiocyte lineage

Langerhans Cell Histiocytosis of the Mandible

The unusual disorder known as Langerhans cell histiocytosis, which is most frequently seen in children and young adults, is caused by the clonal proliferation of Langerhans cells. Even if clinical signs and radiographic evidence of destructive bone lesions may raise suspicion of the disease, a reliable diagnosis without a thorough pathological examination is challenging. This report describes a case of eosinophilic granuloma of the mandible in a nine-year-old child with characteristic radiological, histopathological, and immunohistochemical features.

Langerhans cell histiocytosis: Skin diseases and visceral lesions

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder that belongs to class I histiocytoses and is characterized by infiltration of one or many organs by Langerhans cells to form granulomas. The literature analysis could identify a lot of etiological, pathogenetic, and trigger factors and mechanisms for LCH development, which determine the diversity of the clinical picture and course of the disease. The clinical manifestations of LCH are very variable and depend on the severity of lesions and the age of patients. In addition to skin lesions, there is involvement of one or more visceral organs. Difficulties in diagnosing the disease lead to statistical variations of LCH in different countries of the world and require more attention by physicians of all specialties.

Langerhans Cell Histiocytosis in Children

Langerhans cell histiocytosis (LCH) is a nonmalignant disease characterized by an accumulation of dendritic cells. The disease can affect multiple organs, and the clinical picture ranges from localized bone lesions or skin disease to multiple organ involvement and severe dysfunction. LCH most commonly affects children, with the peak incidence at 1 to 4 years of age. Prognosis is dependent on the number of organ systems involved, the degree to which normal function of the organ system is affected, and the rate of progression of the disease. In the majority of children, the disease is self-resolving. For patients with multisystem disease, it is most commonly treated with steroids and chemotherapeutic agents including prednisone, vinblastine, and mercaptopurine. Although LCH is not considered a malignancy, the pediatric oncology nurse plays a key role in disease management because these patients are often followed in inpatient and outpatient oncology settings. This article provides nurses with insight about the pathophysiology and treatment modalities of LCH and prepares the nurse to provide confident comprehensive nursing care and to educate patients and families.

Langerhans cell histiocytosis: current insights in a molecular age with emphasis on clinical oral and maxillofacial pathology practice

Langerhans cell histiocytosis (LCH) commonly involves the oral and maxillofacial region, and comes to the attention of dental practitioners when a patient presents with orofacial pain and a bony or soft tissue lesion. This is a relatively rare entity, which has made it difficult to investigate the clinical, biologic, and molecular aspects of the disease. Treatment protocols are not well defined, particularly in adults. During the past decade, the Histiocyte Society has formulated various LCH categories, based on risk stratification, and treatment protocols for the pediatric population. Adult trials are currently available through the Histiocyte Society. Although there has been considerable controversy, the neoplastic nature of LCH has been established by demonstrating clonality. LCH symptoms and the development and persistence of LCH lesions have been ascribed to a "chemokine/cytokine storm" due to autocrine and paracrine mechanisms. Discovery of biologic, cytogenetic, and molecular abnormalities in LCH have already affected treatment by providing novel therapeutic targets.

Migration of dendritic cells into lymphatics-the Langerhans cell example: routes, regulation, and relevance

Dendritic cells are leukocytes of bone marrow origin. They are central to the control of the immune response. Dendritic cells are highly specialized in processing and presenting antigens (microbes, proteins) to helper T lymphocytes. Thereby, they critically regulate further downstream processes such as the development of cytotoxic T lymphocytes, the production of antibodies by B lymphocytes, or the activation of macrophages. A new field of dendritic cell biology is the study of their potential role in inducing peripheral tolerance. The immunogenic/tolerogenic potential of dendritic cells is increasingly being utilized in immunotherapy, particularly for the elicitation of antitumor responses. One very important specialization of dendritic cells is their outstanding capacity to migrate from sites of antigen uptake to lymphoid organs. Much has been learned about this process from studying one particular type of dendritic cell, namely, the Langerhans cell of the epidermis. Therefore, the migratory properties of Langerhans cells are reviewed. Knowledge about this "prototype dendritic cell" may help researchers to understand migration of other types of dendritic cells.

Clinical aspects of Langerhans cell histiocytosis

Langerhans cell histiocytosis remains an enigmatic disease with protean manifestations. It may be self-limited in some, whereas in others, even intensive treatment is unsuccessful. The outcome depends on whether vital organ function is compromised at diagnosis or shortly thereafter, in which case the prognosis is grave.

Nosology and pathology of Langerhans cell histiocytosis

The pathology of LCH is continuing to be defined and diagnostic features clarified as unprecedented research is done. Although the etiology of LCH remains unknown, new information on cytokines, viruses, immunologic dysfunction, cell surface antigen expression, and clonality in the disease are providing essential pieces of the puzzle.

Langerhans cell histiocytosis in children under 2 years of age

This is a retrospective study of 55 children under the age of 2 years diagnosed with Langerhans cell histiocytosis (LCH). They were classified according to age and organ function and dysfunction following Lahey's criteria. The studied population was divided into four groups by age of diagnosis (0-6, 7-12, 13-18, and 19-24 months). Statistical analysis showed no significant difference in outcome between age groups, although the population under 6 months had a 81.3% fatality rate. The presence of organ dysfunction was a major cause of death in all age groups, being statistically significant in outcome (P > 0.005) compared with patients without organ dysfunction. The presence of thrombocytopenia and/or respiratory dysfunction was also highly associated with a fatal outcome. In the surviving population, no second malignancies have been reported. The late secondary effects of therapy include endocrine, orofacial, and osseous pathologies.

Langerhans cell histiocytosis

The first major stride toward understanding LCH was taken when ultrastructural studies identified the proliferating cells as part of the Langerhans (dendritic) cell system. Another step forward was the definition of the morphologic, immunohistochemical, and clinical criteria needed for the diagnosis of LCH. Meanwhile, modern imaging studies have disclosed lesions that were not previously visible, especially those in the brain and the pituitary gland. These advantages have had a major impact on clinical management by making it possible to compare data from different institutions and to centralize coherent clinical and therapeutic data. Moreover, the agreement concerning diagnostic criteria provides a solid foundation for current clinical trials and for laboratory research regarding the possible roles of the immune system, clonality, and cytokines in the etiology of LCH.