Nodular secondary syphilis in an immunocompetent woman: Case report and literature review

A 46-year-old woman presented with slightly itching, painless erythematous nodules on the face, neck, and genital area. Initial differential diagnoses included cutaneous lymphoma. We performed punch biopsy on her neck. In histopathology, interface dermatitis with some nodular infiltration of numerous neutrophils and plasma cells was observed, therefore, serologic tests for syphilis were performed. Owing to positive serologic test results and dramatically improved skin lesions after treatment with benzathine penicillin, nodular secondary syphilis was diagnosed. Nodular skin lesions in secondary syphilis are uncommon and often misleading. Our case suggests secondary syphilis should be considered in the differential diagnosis of nodular lesions.