<prompt> Birbeck granules in the cytoplasm are seen in-Mast cellsLangerhans cellsThrombocytesMyelocytes  <response>: Birbeck granules, also known as Birbeck bodies, are rod shaped or tennis-racket cytoplasmic organelles with a central linear density and a striated appearance. First described in 1961 where they were simply termed characteristic granules, they are solely found in Langerhans cells. Although pa of normal Langerhans cell histology, they also provide a mechanism to differentiate Langerhans cell histiocytoses which are a group of rare conditions collectively known as histiocytoses from proliferative disorders caused by other cell lines. Formation is induced by langerin. 