e With the reemergence of syphilis, it is important that both clinical and public health practitioners recognize the various clinical manifestations of this disease (formerly known as "the great imitator") and become familiar with the newer diagnostic tests. Here we report the first case of tonsillar syphilis diagnosed by PCR. CASE REPORT In October 2014, a 58-year-old homosexual male in a long-term exclusive relationship with a man presented to the Gay Men's Health Clinic at Our Own Health Centre in Winnipeg, Manitoba, Canada, with a 2-week history of sore throat and left otalgia. He confirmed that he still had only one partner. On examination, his left tonsil was unusually smooth, red, and quite enlarged. His left tonsillar lymph node was tender and was significantly enlarged to 2.5 to 3 cm in diameter. The result of otoscopy of the left ear was normal, and he was given a presumptive diagnosis of viral tonsillitis. A throat swab for beta-hemolytic streptococci was negative by culture. He declined sexually transmitted infection (STI) screening at his first visit.He returned a week later feeling anxious because he remembered that he had had an extrarelationship contact involving oral sex with another man at a party about 8 weeks earlier (that was approximately 5 weeks prior to the onset of otalgia). He stated he had never received anal sex. On examination, there was now a thin film of white slough on the surface of his left tonsil with no other lesions or patches found in his mouth. He was treated with penicillin V (600 mg every 12 h [q12h]) for 12 days, pending return of laboratory investigations ordered on the basis of the revised history provided and consent for STI screening. A throat swab for culture and a urine specimen for a nucleic acid amplification test (NAAT) were both negative for Neisseria gonorrhoeae. A direct fluorescent antibody assay (DFA) of a throat swab and a NAAT of urine specimens were both negative for Chlamydia trachomatis. A second throat swab taken for routine culture was again negative for beta-hemolytic streptococci. A serum sample was sent for syphilis, hepatitis B virus (HBV), and human immunodeficiency virus (HIV) serology at the Cadham Provincial Public Health Laboratory in Winnipeg, Manitoba, Canada. The patient had previously tested negative for syphilis serology by the use of a treponema-specific antibody a year prior to the current visit. Because of his clinical presentation and the history that he provided, as well as the ongoing syphilis outbreak happening among men who have sex with men (MSM) in Winnipeg, a throat swab (Dacron in viral transport medium at 4°C) was also sent to the National Microbiology Laboratory (NML) in Winnipeg, Canada, for syphilis PCR testing. When the tonsil was swabbed for testing, a shallow erosion was revealed with superficial bleeding. He subsequently tested negative for both HBV (by a surface antigen test) and HIV (by an HIV-1/2 antibody plus HIV p24 antigen combo assay). Syphilis serology results were as follows: Treponema pallidum antibody posi...