Armand Trousseau first described this finding in the 1860s; he later found the same sign in himself, was subsequently diagnosed with pancreatic cancer and died soon thereafter.^[6] Dr. Trousseau presciently attributed thromboembolism in malignancy to changes in blood composition rather than local inflammatory or mechanical forces. By correlating clinical observation with surgical and autopsy findings, Dr. Trousseau recognized that a localized cancer could induce a generalized hypercoagulable state in which thrombosis could occur elsewhere in the body, such as in extremities with visceral malignancy. Dr. Trousseau described several cases in which recurrent thrombosis was the presenting feature of visceral cancer, and his confidence in the utility of this connection led him to say, “So great, in my opinion, is the semiotic value of phlegmasia in the cancerous cachexia, that I regard this phlegmasia as a sign of the cancerous diathesis as certain as sanguinolent effusion into the serous cavities.”

Some malignancies, especially gliomas (25%), as well as adenocarcinomas of the pancreas and lung, are associated with hypercoagulability (the tendency to form blood clots) for reasons that are incompletely understood, but may be related to factors secreted by the tumors, in particular a circulating pool of cell-derived tissue factor-containing microvesicles.^[7] Some adenocarcinomas secrete mucin that can interact with selectin found on platelets, thereby causing small clots to form ^[8][9]

In patients with malignancy-associated hypercoagulable states, the blood may spontaneously form clots in the portal vessels, the deep veins of the extremities (such as the leg), or the superficial veins anywhere on the body. These clots present as visibly swollen blood vessels (vasculitis), especially the veins, or as intermittent pain in the affected areas.

Template:Eponymous medical signs for oncology

Template:WikiDoc Sources