Humans Lesion on a nose. Human<unk>  is characterized by abnormal proliferation of Langerhans cells (LCs). LCs are antigen-presenting cells derived from dendritic cells. In humans,<unk> s are considered as a benign tumors that occurs mainly in children and adolescents.<unk>  is a quite rare condition, and its incidence is higher in white than in black population, also slightly more affecting males than females.<unk>  develops in 4-5 children (aged under 15) per million/year and in 1 or 2 adults per million/year. The etiology of<unk>  is not fully understood yet. However, the onset of abnormal LC proliferation may be triggered by viral stimuli (EBV, Human Herpes virus 6), bacterial toxins or defective regulation of IL-1 and IL-10 production. Another possible explanation may be a defect in Ras/MAPK signaling pathway due to mutation of signaling proteins. Particularly, it was published that about 50% of the<unk>  cases had mutated BRAF V600 E gene and about 21% displayed a mutation in MAP2K1. Signs and symptoms Clinically, single or multiple lesions are present mostly on the axial skeleton - on the skull, spine, ribs, pelvis and long bones. Specifically, thoracic spine and frontal bone within the skull are the most affected in children. On the other hand, cervical spine and jaw bone are the major spots of<unk>  lesions in adults. Symptoms of<unk>  include stiffness, local pain, edema of surrounding tissues, posture change, and many others, depending on the affected bone. Lung<unk>  is even less common. Its prevalence has not been published, however, lung<unk>  was already diagnosed in approximately 5% of all lung biotic samples. Such condition may be asymptomatic, but also a non-productive cough, dyspnea, chest pain, fatigue, and spontaneous pneumothorax can occur. Higher risk of lung<unk>  is being associated with smoking. Diagnosis Diagnostic options of<unk>  comprise X-ray, CT and MR. Histopathological examination of the bioptic sample is focused on the presence of mononuclear LCs with prominent nuclear grooves (coffee bean shaped nuclei) with addition of eosinophils. Such examination also utilizes CD1 and CD207 (Langerin) staining. Electron microscopy examination of the sample is based on detection of Birbeck granules, specific "tennis racquet" shaped inclusion within cytoplasm of LCs. Treatment Single lesions spontaneously regress often, especially in children, thus are followed up in regular intervals. Patients suffering spinal lesions are immobilized to minimize the pain. More complicated cases with multiple lesions should be treated with corticosteroids, particularly with an intralesional injection of methylprednisolon. Corticosteroids also represent an option for pulmonary<unk>  treatment. Operative treatment includes bone grafting and surgical fixation. In advanced stages of the disease, lung transplantation may be required. High-risk patients with multiple lesions (CNS-risk bones, lungs) may undergo chemotherapy.
Eosinophilic granuloma
Ewing's sarcoma
Fibrin ring granuloma
Central giant-cell granuloma
Plasma cell granuloma
Peripheral giant-cell granuloma
Silicone granuloma
Silica granuloma