Novel radiographic presentation of primary syphilis of the tonsil

A 61-year-old HIV+ male presented to an infectious disease clinic with a complaint of sore throat. A painless ulcerated mass was discovered on the right tonsil resulting in further evaluation with a CT scan of the neck. Imaging confirmed the presence of a mass centered on the palatine tonsil and associated lymphadenopathy. A presumptive diagnosis of HPV-related squamous cell carcinoma was made due to patient risk factors. However, multiple biopsies found no evidence of carcinoma, but instead revealed the presence of spirochetes that stained positive for T Pallidum. Soon after, the patient developed the characteristic copper-red maculopapular rash of secondary syphilis, indicating that the tonsillar mass was, in fact, a primary chancre. Since such chancres are most often found externally in the genital or anal region, they are seldom radiographically characterized, placing them low on the differential diagnosis for most radiologists. A high index of suspicion could aid future radiologists in placing primary syphilis higher on the differential diagnosis in similar cases in which the patient has appropriate risk factors, such as a known history of genital-oral sexually transmitted infections or an immunocompromised state. Prompt recognition of the nature of a primary syphilitic lesion can lead to rapid resolution of symptoms following treatment with intramuscular benzathine penicillin G, as eventually occurred in this case.