<prompt> All of the following may lead to plaque formation exceptPityriasis roseaPsoriasisPemphigusLichen planus  <response>: Pemphigus vulgaris is a immunobullous disorder characterised by formation of flaccid blisters in skin and mucous membranes. other options lesions are characterised by papules and plaques. iadvl textbook of dermatology page 1088 