Abstract
Syphilis is a sexually transmitted infection caused by the spirochete Treponema pallidum (TP) subspecies pallidum. Syphilis can be transmitted via contact with infected bodily fluids, such as blood or semen, congenital infection, blood transfusion, or organ transplantation. After a brief incubation period, the disease manifests with signs and symptoms such as genital ulcers, erythematous papules on the palms and soles, fever, and lymphadenopathy. The clinical presentation of syphilis is varied, making its diagnosis challenging. Syphilitic ulcers or erosions (hard chancres) may occur in extragenital regions, and the disease may present as isolated lymphadenopathy without skin lesions. In some cases, lymphadenopathy accompanied by elevated levels of inflammatory markers may mimic hematologic malignancies. Herein, we report a rare case of syphilis associated with genital and extragenital chancres, as well as inguinal lymphadenopathy, in a 31-year-old man. The patient developed a finger ulcer and painless swelling of the left inguinal lymph node, initially suspected to be a skin infection and treated with topical and oral antibiotics, but with poor improvement. During treatment, systemic symptoms such as fever, malaise, joint pain, and loss of appetite emerged, and blood tests showed elevated C-reactive protein and soluble interleukin-2 receptor levels, suggesting suppurative lymphadenitis or hematologic malignancy. Although a lymph node biopsy was considered, a genital ulcer appeared later, raising suspicion of syphilis. TP antibodies were positive, and titers of quantitative rapid plasma reagin and TP antibodies were high, leading to a diagnosis of syphilitic chancres and lymphadenitis. After two months of amoxicillin treatment, the clinical symptoms and blood test results improved. This case highlights the potential time lag in the appearance of chancres in multiple regions and shows that syphilitic lymphadenopathy may mimic hematologic malignancies.