A 25-year-old man presents with painless, progressive, non-tender inguinal lymphadenopathy with a bubonic swelling that has developed a groove sign. The most likely diagnosis and causative organism are:
- A Chancroid — Haemophilus ducreyi
- B Donovanosis — Klebsiella granulomatis
- C Lymphogranuloma venereum — Chlamydia trachomatis L1, L2, L3 ✓
- D Primary syphilis — Treponema pallidum
Correct answer: C. Lymphogranuloma venereum — Chlamydia trachomatis L1, L2, L3
Explanation
The groove sign of Greenblatt — a groove in the inguinal region caused by enlarged lymph nodes above and below the inguinal ligament (Poupart's ligament) — is pathognomonic of lymphogranuloma venereum (LGV). LGV is caused by Chlamydia trachomatis serovars L1, L2, L3. The primary genital lesion (transient painless ulcer/papule) is often missed; the secondary stage presents with painful fluctuant inguinal bubo +/– groove sign. Diagnosis is by complement fixation titre >1:64 or micro-IF.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.