Lymphogranuloma venereum presenting as a giant rectal ulcer with inguinal lymphadenitis: a case report.

Anorectal lymphogranuloma venereum (LGV) can mimic rectal malignancy, but diagnosis may be challenging when LGV-specific serovar testing is unavailable. A 26-year-old man who has sex with men presented with hematochezia and increased bowel movement frequency. Colonoscopy revealed a large deep rectal ulcer with mucopurulent exudate, and pelvic magnetic resonance imaging showed rectal wall thickening with regional lymphadenopathy, raising concern for rectal cancer. Histopathology showed inflammatory changes without malignancy. Rectal secretion testing was positive for Chlamydia trachomatis RNA, and the patient was clinically diagnosed with probable anorectal LGV. Oral doxycycline 100 mg twice daily for 21 days led to marked ulcer regression at 3 weeks and near-complete mucosal healing by 6 weeks. This case highlights the importance of considering sexually transmitted proctitis in young men who have sex with men patients with atypical rectal ulcers.