Ultrastructural observations on 'foam cells' and the source of their lipid in verruciform xanthoma.

Verruciform xanthomas occur on mucocutaneous surfaces and are characterized by hyperkeratosis, acanthosis, and the occurrence of "foam cells" stuffed with lipid surrounding capillaries in the dermis between rete pegs. Ultrastructural examination of a lesion on the penis revealed the presence of melanocytes with many lipid droplets in the basal layer of the epidermis. We suggest that they are a major source of the lipid of the "foam cells." However, this study provides no information as to the nature or lineage of the "foam cells."