Granulomatous Folliculotropic Secondary Syphilis: An Unusual Histopathological Clue.

Abstract: Syphilis is a sexually transmitted disease that can present a wide variety of clinical and histopathological manifestations. We present the case of a 75-year-old patient with a persistent maculopapular rash on the trunk and extremities, in which the biopsy showed an exclusively perifollicular granulomatous infiltrate. In the immunohistochemical staining with anti-Treponema pallidum antibodies, spirochetes scattered within the perifollicular inflammatory infiltrate were identified. These findings together with the serological analysis allowed the diagnosis of secondary syphilis. Folliculotropic nonalopecic syphilis is rare, and the pathogenic mechanisms that cause this specific tropism are unknown. On the other hand, granulomatous inflammation is a pattern typically described in tertiary syphilis but also occasionally found in secondary syphilis. We present a case of secondary syphilis with the combination of both histopathological findings, an uncommon constellation for dermatopathologists to consider.