Birbeck granules in the cytoplasm are seen in-: (A) Mast cells, (B) Langerhan's cells, (C) Thrombocytes, (D) Myelocytes
Answer is B. 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.