Atypical Morphology of a Typical Mycobacterial Infection

Area of Science:

• Dermatology
• Infectious Diseases
• Microbiology

Background:

• Facial nodules can present diagnostic challenges, with differentials including leishmaniasis, keratoacanthoma, and basal cell carcinoma.
• Cutaneous manifestations of tuberculosis, particularly lupus vulgaris, require careful evaluation, especially in endemic regions.

Observation:

• A 24-year-old woman presented with asymptomatic facial nodules. Initial investigations, including smears and cultures, were negative for common pathogens.
• Histopathology revealed non-caseating epithelioid granulomas. A strongly positive Mantoux test (MT) suggested latent tuberculosis.

Findings:

• Despite atypical morphology for lupus vulgaris, the positive Mantoux test and granulomatous inflammation led to a diagnosis of cutaneous tuberculosis.
• Antitubercular therapy (ATT) resulted in a dramatic clinical response with complete healing within six months.

Implications:

• This case underscores the importance of considering cutaneous tuberculosis in the differential diagnosis of facial lesions, even with non-classical presentations.
• Early diagnosis and treatment with ATT are crucial for favorable outcomes in cutaneous tuberculosis, preventing disfigurement.