Catastrophic antiphospholipid syndrome: an orchestra with several musicians.

on antiphospholipid antibodies. This registry is a database in a web-based format that includes all patients with CAPS published or reported directly to the CAPS Registry Project Group. Their results are freely available on the web site: https://ontocrf. costaisa.com/en/web/caps. In the present issue of this journal, De Meis et al. [4] describe the development of CAPS in four patients with malignancies; in all cases the catastrophic episode was triggered by an infection, and in two cases it followed a surgical procedure. The pathophysiology of CAPS is not yet known. In fact, most patients with circulating aPL3 do not develop a thrombosis. This is why an exposure to a second hit has been proposed as mandatory to trigger the thrombotic event [5]. In CAPS, the main precipitating factors are infectious agents – found in about 50% of patients – as well as malignancies and surgical procedures responsible for almost 20% of the cases [6]. However, none of them has been found to be sufficient for the development of CAPS. Most likely, different conditions have a role in increasing the chance of a clot developing, by enhancing pro-thrombotic factors or by decreasing the effect of natural coagulation inhibitors. The increased risk of thrombosis in patients with malignancy was first described in the 19th century by Trousseau [7], who observed the peculiar presence of thrombophlebitis in patients with cancer. Several explanations of this increased risk have been proposed, such as the secretion of pro-coagulant substances by tumor or