Factor XIIIa-positive dendrocyte rarefaction in Ehlers-Danlos syndrome, classic type.

The Ehlers-Danlos syndrome (EDS) represents a heterogeneous group of connective tissue disorders recognized by distinct clinical, microscopic, and biochemical aspects. In particular, some histologic and ultrastructural clues have been reported in the literature. We present a novel immunohistochemical aid to the diagnosis of the most frequent type of EDS. Factor XIIIa-positive dendrocytes are almost absent in the reticular dermis and markedly reduced in number and size in the adventitial dermis. By contrast, the densities of vimentin-positive cells and CD34-positive cells were unremarkable. The biologic significance of this finding is unknown. However, at least a subset of dermal dendrocytes interacts with fibroblasts. This mechanism could be affected in the classic form of EDS.