The antiphospholipid syndrome produces acute occlusions of arteries and veins. This syndrome can cause a multiple organ systems failure whose outcome is often fatal. The authors report a case of the primary, antiphospholipid syndrome characterized by this fatal outcome, a so-called "devastating" syndrome following pulse steroids. In this patient, the antiphospholipid antibodies had been found after presenting bone-marrow fat necrosis, which led to extensive lesions of knees, hips and shoulders. Damage to the cell membranes in necrotic lesions might have promoted the immune response against phospholipids. The potential risks of pulse doses of steroids in the antiphospholipid syndrome are documented by the present observation, which also suggests that antiphospholipid antibodies should be determined in cases of fat necrosis of all origins.