Enlarged inguinal lymph nodes generally suggest the possibility of syphilis, but such enlargement caused by syphilis commonly appears in the secondary or tertiary stages of the disease. In the early primary stage of syphilis, it is rare to see swollen inguinal lymph nodes; the symptoms are mostly seen on the external genitals, including soft and hard chancres. As syphilis progresses, it may gradually lead to swelling of the inguinal lymph nodes, including other superficial lymph nodes. However, enlargement of the inguinal lymph nodes alone cannot conclusively determine that the cause is syphilis. Other conditions such as bacterial lymphadenitis, lymph node tuberculosis, or lymphoma could also cause swollen inguinal lymph nodes. Therefore, to diagnose whether it is caused by syphilis, it is crucial to consider the results of syphilis serological tests and specific pathological puncture findings.