Intracellular Treponema pallidum in cells of a syphilitic lesion of the uterine cervix.

In an electron microscopic study of biopsy tissue from an ulcer of the human cervix uteri, organisms morphologically identical to T. pallidum were observed. Large numbers of the organisms were seen lying among collagen fibrils and between cells. T. pallidum was seen within vacuoles of some fibroblasts and epithelial cells. Within the nucleoplasm of several cells, treponemes were observed, surrounded by a clear zone which might represent a mucopolysaccharide outer layer. The siameter of the organisms was 171 nm., and the diameter of the external axial filaments was 25 nm., dimensions similar to those reported by others for T. pallidum.