Introduction
Syphilis is a chronic systemic infectious disease caused by the spirochete bacterium
Treponema pallidum. It is a sexually transmitted infection (STI) that can present with various histological features depending on the stage of the disease. Understanding these histological changes is crucial for accurate diagnosis and effective treatment.
Primary Syphilis
The primary stage of syphilis is characterized by the formation of a
chancre, typically at the site of inoculation. Histologically, the chancre is marked by intense inflammatory infiltration. This includes a dense mononuclear infiltrate composed predominantly of
lymphocytes and
macrophages. Endothelial swelling and proliferation, along with perivascular plasma cell infiltration, are also common features.
Secondary Syphilis
In secondary syphilis, the infection disseminates, leading to widespread mucocutaneous lesions. Histologically, these lesions show a characteristic lichenoid tissue reaction. There is a prominent inflammatory infiltrate comprising
plasma cells, lymphocytes, and histiocytes. The epidermis often exhibits acanthosis, with some degree of spongiosis and parakeratosis.
Condylomata lata, which are moist, wart-like lesions, display papillomatous hyperplasia and a dense inflammatory infiltrate.
Tertiary Syphilis
Tertiary syphilis can affect multiple organ systems, leading to varied histological presentations. One of the hallmark features is the
gumma, a granulomatous lesion. Histologically, gummas are characterized by central coagulative necrosis surrounded by palisading histiocytes and a peripheral rim of plasma cells and lymphocytes.
Cardiovascular syphilis often involves the aorta, leading to aortitis with plasma cell-rich infiltrates and destruction of the elastic tissue.
Neurosyphilis
Neurosyphilis can occur at any stage of the disease. Histologically, it may present with chronic meningitis, characterized by lymphoplasmacytic infiltration of the meninges. In more advanced cases, parenchymal involvement can lead to
tabes dorsalis, marked by degeneration of the dorsal columns of the spinal cord and loss of myelinated nerve fibers.
Diagnostic Techniques
Histological examination of syphilitic lesions often employs special staining techniques.
Silver stains (e.g., Warthin-Starry) can highlight the presence of Treponema pallidum. Immunohistochemical staining using antibodies against Treponema pallidum is also a valuable tool for identifying the spirochetes within tissue samples.
Conclusion
Understanding the histological features of syphilis is essential for pathologists and clinicians in diagnosing and managing this complex disease. The diverse histopathological changes observed in different stages of syphilis reflect the systemic nature of the infection and underscore the importance of comprehensive histological evaluation in affected patients.
