Dendrocytes in verruga peruana and bacillary angiomatosis.

Verruga peruana and bacillary angiomatosis are two cutaneous diseases characterized by angiomatous growths linked to the presence of rickettsia-like organisms. These lesions are currently considered to be endothelial hyperplasias and to share many features. By immunohistochemistry and computerized image analysis, we studied the presence of factor-XIIIa-positive dendrocytes in these lesions and compared our data with similar research in capillary angiomas and normal skin. Other cell lines were studied by Ulex europaeus and by antibodies to the L1 antigen and to the von Willebrand factor. Dendrocytes were identified in the three types of angiomatous growth. They were numerous and appeared plump, but no more dendritic than in normal skin. Verruga peruana and bacillary angiomatosis should therefore be viewed as combined growths of endothelial cells and dendrocytes. The biological link between these two types of cells is emphasized.