[Microcirculation in white atrophy].

There are two clinical phenomena which, owing to the French School, are still subject to violent criticism: the phenomenon described by M. Raynaud (1862) and the white atrophy termed Milian's (1929). Perhaps badly defined by the authors, the facts have been reviewed, but microcirculation - that of gauges less than 30 to 50 m - does not occupy the whole picture. The proof is that in direct capillaroscopy, functional explorations and biopsy are strikingly monotonous and lacking in exactitude. Capillaroscopy provides the usual aspects of cicatrization, "capillary" neogenesis and their histogenic disorders: central avascular zone, corona limited with loops in "club" formation, or in "clusters" owing to their confluence, "key" loops at the periphery near to the normal loops. These "neocapillaries" pose problems of the immaturity of the neovascular elements and of hydraulics in venous stasis. Of course, there are disorders of capillary permeability, and these are linked especially with vascular neogenesis, but it would not be reasonable to speak of "cutaneous infarctus", or "vascularitis", the necessary criteria being absent. On the contrary, we believe that it all comes down to a "histoangiopathy" by deterioration of the pericapillary sheath of proteoglycanes and of the interstitial conjunctiva. The anomalies are of the type of the deteriorations in plastic polymers and the apparatus of the endarterial bloc, which are included. A "trapping" of the leucocytes in the declivitous areas must also play a part.