<prompt> Birbeck granules in cytoplasm is seen in -Langerhans cell histiocytosisHodgkins lymphomaNon hodgkins lymphomaGastrointestinal stromal tumor  <response>: Ans. is a i.e., Langerhans cell histiocytosis Birbeck granules are characteristic of langerhans cell histiocytosisTumour cells in the laneerhan cell histiocytosis are derived from dendritic cells and express :-o S-100o CDlao HLA-DRo These cells are characterized by the presence of birbeck granules in their cytoplasm unde rthe electron micro-scope, Birbeck granules have pentalaminar, rodlike tuular appearance and sometimes a dilated terminal end itennis-racket appearance 