case_images: PMC11194011_01
case_images: (A) Red ring plaque around the patient's anus. (B and C) Histopathological examination of the red patches of skin with ridges at the edges showed parakeratosis, epidermal hyperplasia, and a dense band of inflammatory cells, mainly lymphocytes and plasma cells, at the junction between the lower epidermal process and the true epidermis.(hematoxylin-eosin staining, original magnification X50, X200, respectively). (D and E) Immunohistochemical staining showing numerous spirochetes in the lower part of the epidermis (Immunostain spirochete stain, original magnification X50, X200, respectively) (F) After 2 weeks of penicillin intravenous treatment, the perianal rash subsided than before, leaving pigmentation.
case_images: IDR-17-2463-g0001.jpg
case_images: PMC11194011_01_IDR-17-2463-g0001.jpg
case_images: f0001
case_images: Physical examination revealed patchy erythema of varying sizes around the anus, with circular raised plaques at the edges, and a few white scales overlying them (Figure 1A). Histopathological examination of the skin lesion revealed parakeratosis, epidermal hyperplasia, and a dense band of inflammatory cells in the lower part of the epidermis and dermo-epidermal junction, mainly lymphocytes and plasma cells (Figure 1B and C). Immunohistochemical staining for T. pallidum confirmed positivity (Figure 1D and E). After two weeks of intravenous penicillin treatment, the perianal rash subsided, leaving pigmentation (Figure 1F).