Luetic lymphadenopathy despite negative serology.

Area of Science:

• Infectious Diseases
• Clinical Pathology
• Immunohistochemistry

Background:

• Syphilis diagnosis relies heavily on serological tests (treponemal and non-treponemal).
• False-negative results in syphilis testing are possible, though rare for both test types to be negative simultaneously.
• Clinical presentation of syphilis can be highly variable, making diagnosis complex.

Observation:

• A case of luetic lymphadenopathy was diagnosed via histological examination and immunohistochemical staining for Treponema pallidum.
• The patient presented without skin lesions and with negative serological test results for syphilis.
• The negative serology was suspected to be due to prior inadequate antibiotic therapy.

Findings:

• Histopathology and immunohistochemistry confirmed syphilis despite negative serological tests.
• This case underscores the potential for atypical presentations of syphilis.
• Negative serological results in syphilis may be influenced by prior antibiotic exposure.

Implications:

• Clinicians should maintain a high index of suspicion for syphilis even with negative serology, particularly in patients with a history of antibiotic use.
• The impact of widespread antibiotic use on the sensitivity of syphilis serological tests requires further investigation.
• Histological and immunohistochemical methods serve as crucial diagnostic tools when serology is inconclusive or negative in suspected syphilis cases.