A child presents with a single warty plaque on the knee with central clearing. AFB staining is positive and biopsy shows pseudoepitheliomatous hyperplasia with mixed granulomatous infiltrate. The most likely diagnosis is:

• A Lupus vulgaris
• B Scrofuloderma
• C Lichen scrofulosorum
• D Tuberculosis verrucosa cutis ✓

Explanation

Tuberculosis verrucosa cutis (TBVC) presents as a warty plaque, typically on the dorsum of hands/feet or knees, in individuals with moderate immunity. It represents a secondary inoculation type — occurring in previously sensitized individuals (positive Mantoux). Histopathology shows pseudoepitheliomatous hyperplasia of the epidermis overlying a mixed suppurative and granulomatous infiltrate. AFB may be found in small numbers. Lupus vulgaris appears as apple-jelly nodules on the face. Lichen scrofulosorum shows lichenoid follicular papules.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.