<prompt> Row of tombstone is seen in which skin disorder:Pemphigus vulgarisPemphigus foliaceousParaneoplastic pemphigusBullous pemphigoid  <response>: Ans. A. Pemphigus vulgaris Pemphigus vulgaris is characterized by following signs:1. Bulla spread sign2. Perilesional, and distant Nikolsky sign3. Tzanck smear: Acantholytic cell Histopathology shows suprabasal blister with row of tomb stone appearance of basal cells. Direct immunofluorescence from perilesional skin demonstrated intra epidermal IgG deposits in a fishnet pattern. 