Abstract
Syphilis is a sexually transmitted disease caused by Treponema pallidum (TP). We report a case of syphilis that was initially suspected as tongue cancer. An 86-year-old man consulted a neighborhood clinic with an approximately one-month history of pain in the right tongue. The result of scraping cytology of the tongue performed at the clinic was classified as class V, squamous cell carcinoma, and the patient was referred to our hospital. Physical examination revealed a mass on the right side of the tongue and a firm cervical mass. Biopsy revealed no evidence of malignancy; however, the imaging findings led to the suspicion of tongue cancer and lymph node metastasis. The results of blood examination revealed that the patient had syphilis, but since the patient showed few other symptoms, we decided to treat the infection after the planned surgery. We performed right partial glossectomy and neck dissection; however, the postoperative histopathology revealed no evidence of malignancy but nonspecific inflammatory changes with TP spirochetes. The incidence of syphilis has increased dramatically around the world, including Japan, during the last 20 years, and it no longer remains a rare disease. Therefore, syphilis should be included in the differential diagnosis of oral or cervical masses.