Birbeck granulesBirbeck granule is a rod shaped or tennis racquet shaped organelle present in Langerhans cells. It is 200 to 400 nm long and 33 nm wide with a zipper like appearance.
Birbeck granules are a hallmark of Langerhans cells. They can be demonstrated by electron microscopy in non-neoplastic Langerhans cells, as well as in neoplasms of Langerhans cell lineage. Langerin, the key component of Birbeck granules, can also be demonstrated in these cells by immunohistochemistry.