Cutaneous Secondary Syphilis Resembling Non-Melanoma Skin Cancer.

Area of Science:

• Dermatology
• Infectious Diseases
• Pathology

Background:

• Cutaneous manifestations of secondary syphilis are highly variable.
• This variability can lead to diagnostic challenges and delays.
• Atypical presentations may mimic other skin conditions, such as non-melanoma skin cancer.

Observation:

• A 45-year-old, HIV-positive male presented with a solitary, crusted anterior neck nodule.
• The lesion's appearance and lack of systemic symptoms raised suspicion for non-melanoma skin cancer.

Findings:

• Histopathology revealed a dense plasma cell infiltrate at the dermoepidermal junction.
• Immunohistochemical staining confirmed the presence of numerous Treponema pallidum microorganisms within the lesion.

Implications:

• Physicians should consider syphilis in the differential diagnosis of atypical nodular skin lesions.
• Prompt diagnosis and appropriate antibiotic treatment are essential for managing syphilis and preventing sequelae.
• This case highlights the importance of considering infectious etiologies in dermatological diagnoses.