[Morphology and morphogenesis of psoriasis].

Comprehensive morphologic studies of material from postmortem examinations of 7 psoriatic patients (3 with progressive and 4 with stable psoriasis) indicated systemic progressive involvement of connective tissue and vessel walls--with development of proliferative and destructive vasculitis in the microcirculatory bed--as the underlying morphologic feature of the disease. Excessive epidermal proliferation was due to the damage sustained by basement membranes and to gross disorganization of the connective tissue and vessel walls, which compromised the collagen-mediated regulation of epithelium-mesenchyme interactions.