Langerhans Cell Histiocytosis: Clinical Features and Morphology

🔬Langerhans Cell Histiocytosis. ✅A rare disease, occurring in childhood at a frequency of 3-4 cases per 1 million pediatric population per year, even less frequently in adults. ✅The cause of the disease is unknown. A leading role is attributed to cytokines produced by T-lymphocytes and Langerhans cells in the lesions, which mediate the local accumulation of inflammatory infiltrate (eosinophils, macrophages, giant multinucleated cells). ✅Clinical symptoms include bone involvement – skull vault, tibias, ribs, pelvis, vertebrae, mandible. In 30% of cases, lymph nodes are involved. In 30-40% of cases, skin lesions in the form of dermatoses are observed, less often involvement of the oral mucosa. Bone marrow involvement occurs in children with disseminated forms of the disease. This is accompanied by anemia, thrombocytopenia, and neutropenia. ✅Morphological examination of bone marrow aspirate usually reveals normal cellular composition; single Langerhans cells may be found, but their diagnostic significance is low. Histological examination of bone marrow trephine biopsy is more informative. ✅The diagnosis is confirmed by the detection of proliferation of Langerhans cells expressing CD1a, langerin (CD207), S-100 protein, vimentin, CD68, HLA-DR. ✅Photo source inst:xiaoning.zhang ✅Description source: Lugovskaya S. A., Pochtar M. E. Morphology of bone marrow cells in health and pathology //Tver: Triada. – 2018.