Xanthogranulomatous osteomyelitis
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| Xanthogranulomatous osteomyelitis | |
|---|---|
| Other names | XO |
| Specialty | Infectious disease, orthopedic |
Xanthogranulomatous osteomyelitis is a peculiar aspect of osteomyelitis characterized by prevalent histiocytic infiltrate and foamy macrophage clustering.[1]
The granulomatous tissue largely comprises foam cells of monocyte/macrophage origin positive for KP1, HAM56, CD11b and CD68. Neutrophils, hemorrhagic foci and numerous plasma cells are additional findings.[2][3][4][5] Staphylococcus aureus was isolated in the case reported by Kamat et al.[5] A delayed type hypersensitivity reaction in cell-mediated immunity has been suggested in this type of infiltrate that is composed of macrophages and T cells.[3] T cells are represented by a mixture of CD4+ and CD8+ lymphocytes. Macrophages and lymphocytes show marked expression of HLA-DR antigen.[6] Arguably XO is the bone localization of the xanthogranulomatous process occurring in several other locations.[2]