The biopsy specimen showed parakeratosis with neutrophils overlying an acanthotic epidermis. The dermis contained a lichenoid and perivascular infiltrate composed of numerous plasma cells and lymphocytes. Endothelial swelling was present. Periodic acid–Schiff and Warthin-Starry stain failed to demonstrate organisms; however, the hematoxylin-eosin findings were compatible with a diagnosis of syphilis. The results of a rapid plasma reagin test were positive at 1:64; the results of a fluorescent treponemal antibody-absorption test were also positive.
Multiple Annular Plaques on the Face of a Middle-aged Woman. Arch Dermatol. 2000;136(7):925-930. doi: