Atypical Invasive Presentation of Chlamydia trachomatis Genotype D Mimicking Lymphogranuloma Venereum

Three Chlamydia trachomatis biovars are recognized-trachoma (serovars A-C), urogenital (serovars D-K), and lymphogranuloma venereum (LGV) (serovars L1-L3). Only serovars L1-L3 cause invasive infection with bubo formation. Here, we present an atypical case of C. trachomatis serotype D with clinical presentation of LVG-unilateral inguinal lymph edema plus bubo formation. A 35-year-old male who have sex with men presented to the clinic with unilateral swollen painful right inguinal lymph nodes forming bubo, accompanied by fever up to 39°C and malaise. Complete blood count was tested. Urethral sample for DNA extraction and polymerase chain reaction (PCR) was taken. Ultrasonography and proctoscopy were performed. Fine-needle aspiration from lymph node was tested for malignant cells and PCR diagnostics. A full STI screen was performed. PCR positive for C. trachomatis was detected. The exact classification of C. trachomatis species needed additional genovar-specific C. trachomatis PCR. Surprisingly genotype D instead of LVG L1-L3 was discovered. Co-infection with Mycoplasma genitalium was detected. HIV, Neisseria gonorrhoeae, HSV, and Ureaplasma spp. were negative. Serology excluded syphilis, HBV, HCV, infectious mononucleosis, toxoplasmosis, and cat scratch disease. Malignant cell formation was ruled out. This case highlights the importance for clinicians to consider atypical and invasive presentations of nonLGV C. trachomatis genotypes, as reliance on clinical features alone may lead to misclassification, inappropriate management, and delayed targeted therapy.