Body location | - Head and neck most common
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Clinical appearance | - Cutaneous papules and nodules
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Systemic involvement | | - Associated with renal disease in approximately 20% of cases
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Main findings | - Proliferation of blood vessels of varying sizes lined by plump endothelial cells
- Mild fibrous stromal reaction
| - Florid lymphoid follicles with germinal center formation
- Hyperplastic small blood vessels lined by flat or cuboidal endothelial cells
- Prominent stromal fibrosis
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Infiltrate | - Mixed, lymphocytes and variable number of eosinophils
| - Dense inflammatory infiltrate of lymphocytes, plasma cells, histiocytes, eosinophils
- Eosinophilic microabscesses
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Lymph nodes | | - Preserved nodal architecture, follicular hyperplasia with reactive germinal centers, IgE deposition in the germinal centers
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