[Micromorphologic changes in the skin in primary and secondary (post-thrombotic) chronic venous insufficiency].

The micromorphological alterations in chronic venous insufficiency are characterized by a patchlike distribution. At least in the initial stages, normal skin areas may alternate with regions containing severe alterations. The capillaries may be rarified, or elongated and dilated with formation of glomerulus-like clusters, or they may show proliferation within a granulomatous repair tissue. Pericapillary accumulation of fibrin may be observed only within necrotic tissue surrounding an ulcer. The pericapillary space which is enlarged and edematous in chronic venous insufficiency, cannot be anatomically defined. The interstitial tissue may contain a secondary chronic inflammation with repair function. Finally a hyaline scar tissue with so-called "avascular" fields and dystrophic calcification/ossification may result.