Primary syphilis of the oropharynx mimicking a neoplasm.

Syphilis is surging in Japan and worldwide among both homosexual and heterosexual individuals. Diagnosis can be challenging because syphilis is "the great imitator" and clinical manifestations are highly variable. Oral manifestations of syphilis are usually seen in the second stage and the primary syphilis in the oral cavity is rare. We describe a heterosexual man with isolated tonsillar lesions initially misdiagnosed as pharyngeal lymphoma and subsequently diagnosed as primary syphilis. Clinicians should be aware that isolated oropharyngeal involvement can occur in the primary syphilis and can mimic a neoplasm.