Lupus vulgaris in a pediatric patient: a clinicohistopathological diagnosis.

Lupus vulgaris is the most common form of cutaneous tuberculosis which usually occurs in patients previously sensitized to Mycobacterium tuberculosis. We present a case of a 10-year-old boy who was diagnosed as lupus vulgaris clinically and histopathologically. He had well demarcated, irregularly bordered, pink, infiltrated plaques on his left cheek showing apple-jelly appearance on diascopy. The histopathological examination showed tuberculoid granulomas with Langhans type giant cells. The Mantoux reactivity was in normal limits, and no acid-fast bacilli was found in the lesion, either by direct stained smears or by culture. The lesions showed marked improvement on anti-tuberculosis treatment. We want to emphasize that histopathological examination has diagnostic value in lupus vulgaris in correlation with clinical appearance, when direct analysis or culture is negative.