Foamy macrophages are proinflammatory and express TREM2 in eruptive xanthomas

The accumulation of dermal foam cells, the lipid-laden macrophages is the primary histopathological feature of eruptive xanthomas. Yet, the activation and implications of the foamy macrophages in eruptive xanthomas remain unknown. We investigated foamy macrophage activation and found that these cells are proinflammatory. More interestingly, foam cells in eruptive xanthomas express TREM2, a recently identified marker for lipid-laden macrophages in atherosclerosis and obesity.