Subcutaneous thrombotic vasculopathy syndrome: an ominous condition reminiscent of calciphylaxis: calciphylaxis sine calcifications?

Ischemic skin necrosis can be a cause of severe morbidity and mortality. It can be due to a number of systemic conditions such as (1) thrombotic vasculopathy syndromes, (2) calciphylaxis, (3) septic or cholesterol emboli, and (4) cutaneous vasculitis. We present 3 patients with a clinicopathological syndrome consisting of ischemic skin necrosis associated with histological pattern of subcutaneous thrombotic vasculopathy-extensive microvascular thrombosis confined to small vessels and capillaries of the subcutaneous tissue. All 3 patients were obese and had severe pre-existing medical conditions. Skin biopsies showed intravascular thrombosis involving small arterioles and capillaries of the subcutaneous tissue. Distribution of vascular involvement by thrombotic process was similar to that observed in calciphylaxis, but calcifications were not observed. Two patients died within 3 months of diagnosis. One patient died 2 years after the presentation. Review of 15 biopsies of calciphylaxis revealed areas of subcutaneous thrombotic vasculopathy in 11 cases (73%). Our study shows that subcutaneous thrombotic vasculopathy syndrome is a potentially lethal condition showing overlapping features between thrombotic vasculopathy syndromes and calciphylaxis. Clinicopathological analysis suggests that it may be a rare variant of calciphylaxis sine calcifications or an early prodromal stage of calciphylaxis. This conclusion is in keeping with increasing appreciation of importance of thrombosis and vascular injury in calciphylaxis.