Abstract

Secondary syphilis is known for its clinical and histopathologic mimicry and frequently presents a diagnostic challenge. To emphasize the protean clinical and histopathologic manifestations of secondary syphilis, we present two cases showing an unexpected granulomatous reaction pattern to underscore the unusual histopathologic and clinical manifestations of this disease.

Case-1: A 47-year-old female presented with a one-month history of asymptomatic one-to-two-centimeter erythematous plaques on the trunk and extremities, some with an annular morphology, others with a targetoid appearance. Biopsies from two different plaques showed a lichenoid interface dermatitis with a subjacent granulomatous infiltrate. Additionally, the dermal infiltrate contained neutrophils and scattered plasma cells with a palisade of histiocytes. Neutrophils and leukocytoclastic debris surrounded the small blood vessels where fibrin had deposited. Immunohistochemistry for Treponema pallidum revealed rare organisms along the dermal-epidermal junction, supporting the diagnosis of granulomatous syphilis. The patient was treated accordingly, and the lesions resolved.

Case-2: A 66-year-old male presented with a single, asymptomatic, pink, indurated nodule in the lower lip that appeared one month prior. Clinical examination revealed numerous additional ill-defined papules and patches throughout the trunk and extremities. Biopsies from both the lip and a truncal lesion showed a dense multinodular dermal inflammatory infiltrate composed of epithelioid histiocytes with scattered multinucleated giant cells arranged in variably sized clusters. Multiple intermixed lymphocytes and plasma cells were also present within the clusters. Immunostains for Treponema pallidum highlighted spirochetes in the dermis within the granulomas and around the endothelial cells, confirming the diagnosis of granulomatous secondary syphilis.