Detection of Treponema pallidum by immunocytochemistry of cervical smear: A case report.

Syphilis is an infectious disease caused by Treponema pallidum (T. pallidum). A cervical smear is useful when screening for sexually transmitted diseases; however, T. pallidum is not detected in the usual Papanicolaou smear. We report the detection of T. pallidum by immunocytological examination of a cervical smear. A 22-year-old woman presented with nephrotic syndrome. On admission, we performed screening tests for infections, and her serology was positive for syphilis. A Papanicolaou cervical smear (Thin-Prep) showed slight nuclear enlargement, nuclear irregularity, and mild hyperchromasia in the superficial cells, but no organism was detected. T. pallidum was detected in the remaining specimen using immunocytochemistry. We also detected the T. pallidum DNA in a cervical biopsy specimen by polymerase chain reaction (PCR). Our findings suggest that immunocytological examination and PCR assay examination are useful tests for syphilis diagnosis.