The Fine Structure of the Langerhans Cell Granule

During the last few years increasing attention has been focused on Langerhans cells and their peculiar granules (1-5). These organelles were considered specific products of the intraepidermal dendritic cells (1-3), but recently identical structures have been observed in osseous and pulmonary lesions of histiocytosis X (6). The Langerhans cell granule resembles a tennis racket. It is rodlike with a striated central line and a partly expanded limiting membrane at one end (1-3). Birbeck et al. (1) consider it disc-shaped and suggest that the tennis-racket image represents a formative stage of the granule. The present study provides more information on the fine structural features of this organelle.