The New England Journal of MedicineTuberculosis Verrucosa Cutis

Occupational Exposure Leading to Tuberculosis Verrucosa Cutis in a Veterinarian: Insights on Cutaneous Tuberculosis and Clinical Management

A 59-year-old veterinarian presented with a persistent, painful rash on his right hand, eventually diagnosed as tuberculosis verrucosa cutis, a rare form of cutaneous tuberculosis. This diagnosis was confirmed through metagenomic next-generation sequencing despite negative tissue cultures, highlighting the importance of advanced diagnostic methods in identifying mycobacterial infections. The patient responded well to a 6-month course of antituberculous therapy, speaking to the efficacy of standard treatment regimens even in atypical presentations.

Key Points:

• Patient Presentation: A 59-year-old veterinarian with a 1-year history of a painful rash on his right hand. No other symptoms were reported.
• Physical Examination: Verrucous plaques with thick yellow-brown crusting were observed on the dorsum of the right hand and the medial aspect of the right index finger.
• Histopathology: Biopsy showed pseudoepitheliomatous hyperplasia and tuberculoid granulomas in the dermis.
• Diagnostic Methods:
  • Tissue cultures were negative for mycobacteria.
  • Metagenomic next-generation sequencing identified Mycobacterium tuberculosis.
  • An interferon-γ release assay was positive.
  • Computed tomographic scan of the chest was normal.
• Diagnosis: Tuberculosis verrucosa cutis, a form of cutaneous tuberculosis resulting from direct inoculation of the organism into the skin of previously sensitized individuals.
• Risk Factors: Occupational exposure to mycobacteria, particularly in individuals with frequent contact with livestock.
• Treatment: Initiation of a 6-month course of isoniazid, rifampin, and ethambutol.
• Follow-Up: The rash had abated at 2 months after starting antituberculous therapy.

Throughout the year of 2016, globally, 147,000 confirmed cases and 12,500 fatalities of tuberculosis-affected patients were reported. (WHO)

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