Track

Abstract

Syphilis, a sexually transmitted disease caused by the spirochete Treponema pallidum, has seen a resurgence over the past two decades. Despite an increase in prevalence, contemporary studies examining the clinicopathologic correlates of cutaneous syphilis remain limited. Here we characterize the histopathologic features of cutaneous syphilis cases diagnosed at a single institution since 2013, and explore potential associations with clinical presentation. A review of 26 cases revealed broad, expected variability in clinical features. Notably, 30% of cases did not include syphilis in the differential diagnosis at time of biopsy. Review of histological features revealed several unexpected trends, including granulomatous inflammation in 50% of cases and eosinophils within the inflammatory infiltrate in 40%. Eight percent of cases displayed negative immunohistochemical staining for T. pallidum (with serologic data confirming a diagnosis of syphilis), and an additional 15% were equivocal or very sparse. Cases with negative or sparse T. pallidum staining were also more likely to lack other characteristic histologic features of syphilis, further contributing to diagnostic uncertainty. We did not identify other consistent correlations among clinical presentation, histopathological features, or serological data. These results further confirm the variability of cutaneous syphilis and underscore the importance of clinical and pathological vigilance in its diagnosis.