Primary and secondary syphilis: a histopathological study

We present a study of biopsies taken from skin lesions of 44 patients presenting with primary or secondary syphilis. In most primary lesions erosion or, more often, ulceration was present, with a dense inflammatory infiltrate. In secondary syphilis a wide variety of histological changes was present. Blood vessels were frequently involved, with marked endothelial swelling and often proliferation. Treponemes were demonstrated with the Steiner staining method in all investigated cases of primary syphilis and in 71% of secondary syphilis cases. Treponemes were present throughout the dermis, particularly perivascularly, and in the dermal-epidermal junction zone. In two specimens of secondary syphilis treponemes were located predominantly in the epidermis, but there were always some microorganisms demonstrable in the dermis. The inflammatory infiltrate was often located in a perivascular coat-sleeve-like arrangement. In this study plasma cells and lymphocytes were present in all specimens of primary and secondary syphilis. Syphilitic lesions differed from yaws lesions mostly in the location of treponemes and the affection of blood vessels. In this histopathological study of early syphilis, treponemes did not show the epidermiotropic character of yaws, and blood vessel changes were more pronounced than in yaws. Unfortunately, due to the protean histopathological manifestations described in venereal syphilis and in yaws, these two treponemal diseases cannot always be differentiated on histological grounds alone.