Rod-shaped bodies resembling birbeck granule-like structures in endothelial cells of dermal capillaries in generalized granuloma annulare.

A previous study demonstrated that, in generalized granuloma annulare in the epidermis, the Langerhans' cell section area and the number of Langerhans' cell granules or Birbeck granules per cell section were increased, suggesting an active state of these Langerhans' cells. Reexamination by transmission electron microscopy of the same tissue, but in samples also containing dermal tissue, from the same subjects revealed endothelial cells with rod-shaped bodies resembling Birbeck granules or Birbeck granule-like structures. This finding has not been previously described in blood vessels of human skin and is described here.