For 2 weeks, a 30-year-old homeless man has had an enlarging ulcer on the shaft of his penis.
History. The patient had sexual relations with an unknown partner about 3 weeks earlier. The lesion started as a red papule that quickly eroded to form a painless ulcer with serous discharge; it was associated with asymptomatic swelling in the groin.
The patient denies fever or chills, urethral discharge, and urinary symptoms. He has no history of genital or mouth ulceration. There is no rash or joint swelling and no history of chest pain, dyspnea, palpitations, ankle edema, headache, vision problems, cognitive dysfunction, muscle weakness, paresthesia, syncope, seizures, or ataxia.
The patient smokes 1 pack of cigarettes and drinks 6 beers a day; he uses marijuana regularly. He is a sexually active heterosexual with multiple partners. He takes no medication.
Examination. This fairly well-built and well-nourished man is unkempt but not in undue stress. The heart rate is 74 beats per minute and regular; respiration rate, 20 breaths per minute; blood pressure, 124/72 mm Hg. Hydration status is good. There is no evidence of anemia, clubbing, or cyanosis. Examination of the head and neck is unremarkable. There is no thyroid enlargement.
The patient has a single large, painless, punched-out ulcer on the penile coronal sulcus. The ulcer has wide rolled edges and an indurated base and exudes a clear serous discharge. Mildrubbery, nontender, nonfluctuant inguinal adenopathy is noted on the right side. Other systemic examination results are normal.
Laboratory studies. White blood cell (WBC) count, 7200/µL with a normal differential. Hemoglobin level, 12.9 g/dL; platelet count, 180,000/µL; erythrocyte sedimentation rate, 28 mm/h. Urinalysis results are normal. Gram staining of serous discharge from the ulcer reveals a few WBCs but no organisms. No giant cells are seen on Tzanck testing.
The patient is promptly sent to the public health department for dark-field examination of the serous discharge.
Based on the clinical picture and the initial laboratory findings, what is the most likely diagnosis?
A. Primary syphilis
B. Herpetic penile ulcer
D. Granuloma inguinale
E. Squamous cell carcinoma of the penis
(Answer and discussion begin on the next page.)
FOR MORE INFORMATION:
- Brown DL, Frank JE. Diagnosis and management of syphilis. Am Fam Physician. 2003;68:283-290.
- Centers for Disease Control and Prevention. Sexually transmitted diseases. Treatment guidelines 2002. MMWR. 2002;51(RR-6):1-78.
- Hook EL 3rd, Martin DH, Stephens J, et al. A randomized, comparative pilot study of azithromycin versus benzathine penicillin G for treatment of early syphilis. Sex Transm Dis. 2002;29:486-490.
- Larsen SA, Steiner BM, Rudolph AH. Laboratory diagnosis and interpretation of tests for syphilis. Clin Microbiol Rev. 1995;8:1-21.
- Mitchell SJ, Engleman J, Kent CK, et al. Azithromycin-resistant syphilis infection: San Francisco, California, 2000-2004. Clin Infect Dis. 2006;42:337-345.
- Thompson S, Larsen S, Moreland A. Syphilis. In: Morse SA, Moreland AA, Holmes KK, eds. An Atlas of Sexually Transmitted Diseases and AIDS. 2nd ed. London: Mosby-Wolfe; 1996:18-28.