[Idiopathic white atrophy causing cutaneous thrombotic microangiopathy. Apropos of a case].

Authors report clinical data on a 59-year-old woman, bearing, since 15 years, painful purpuric and necrotizing macules and papules on the legs, leading to white atrophic scars. On examination one could see lesions in various stages of development. Clinical examination and all laboratory investigations were otherwise normal. First cutaneous biopsy led to an erroneous diagnosis of vasculitis with subsequent corticotherapy. Second biopsy displayed numerous fibrinous thrombi inside lumens of superficial dermal capillaries without fibrinoid necrosis of their parietal layer nor inflammatory infiltrate. A diagnosis of white atrophy was made on the coexistence of clinical and histopathological data, according to Shornick's criteria. Drastic improvement of clinical condition was obtained with heparin therapy. White atrophy is a clinicopathological entity first described in 1929 by Milian, then by Nelson in 1955. Authors describe here its main clinical data with diagnostic considerations and pathophysiology.