Abnormal Langerhans cell morphology Absent Birbeck granules in Langerhans cells 2018-05-06T13:41:13Z Birbeck granules (BG) are cytoplasmic organelles that are only found in Langerhans cells (LC). The function of BG is still not completely understood, although most studies point toward an active role in receptor-mediated endocytosis and participation in the antigen-processing/presenting function of LC. This feature refers to the absence of BG in LC, a feature that can be documented by means of electron microscopy.