A 20-year-old man who has multiple sexual partners and does not use barrier precautions has had a non-tender ulcer on his penis for the past week. On physical examination, the 0.6-cm lesion has a firm, erythematous base and sharply demarcated borders. The lesion is scraped, and the microscopic darkfield examination is positive for motile spirochetes. Which of the following inflammatory processes is most likely to accompany this infection?

Infection with Treponema pallidum can lead to syphilitic chancres in the primary stage of syphilis. The chancres are characterized by lymphoplasmacytic infiltrates and by an obliterative endarteritis. Similar lesions also may appear with secondary syphilitic mucocutaneous lesions. Acute inflammation with abscess formation is characteristic of bacterial infections such as gonorrhea. Caseating granulomatous inflammation is more characteristic of tuberculosis or fungal infections. Gummatous inflammation can be seen in adults with tertiary syphilis or in congenital syphilis.