Langerhans cell histiocytosis:
Chapter: 20a
Proliferation of Langerhans type histiocyte, which is a dendritic macrophage normally present in the skin which functions in antigen presentation. Langerhans cells have a folded nucleus with prominent nuclear grooves, and contain a characteristic racquet-shaped ultrastructural inclusion called a Birbeck granule. Langerhans cell histiocytosis has only recently been shown to be a clonal disorder (Cheryl Willman,et al., NEJM, 1994). The clinical course is variable, and three different forms of the disease are recognized. Eosinophilic granuloma is a solitary tumor site, usually involving bone or soft tissue. Hand-Schuller- Christian syndrome is multifocal tumor sites. Letterer-Siwe is the acute disseminated form, occurring in children less than 2 years of age, which involves skin, viscera, and organs of the reticuloendothelial system(spleen, liver, lymph nodes and bone marrow).
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