<prompt> A young boy presented with lesion over his right buttock which had peripheral scaling and central scarring. The investigation of choice would beTzank SmearKOH preparationBiopsySaborauds agar  <response>: The boy is having lupus vulgaris because the lesions have central scarring.Central Scarring is a feature of lupus vulgaris.Diagnosis of lupus vulgaris is confirmed by Biopsy.Remember Feature Central clearing Central Scarring Central Crusting DiseaseTinea corporis Lupus Vulgaris Leishmaniasis InvestigationKOH SmearBiopsyLD body demonstration 