Trousseau syndrome

Trousseau syndrome describes a hypercoagulable state producing recurrent, migratory superficial vein thrombosis, often in unusual sites (e.g., arms, chest), occurring in the setting of an underlying malignancy—most classically mucin-secreting adenocarcinomas of the pancreas, but also seen with lung, stomach, colon, prostate, and ovarian cancers. The pathophysiology involves tumor-derived procoagulant factors: tumor cells (especially mucinous adenocarcinomas) express tissue factor and cancer procoagulant, activating the extrinsic coagulation pathway; mucin can also directly activate platelets and factor X. This leads to a chronic low-grade disseminated intravascular coagulation-like state with increased thrombin generation, platelet activation, and microthrombi formation, causing both venous and sometimes arterial thromboses (nonbacterial thrombotic/marantic endocarditis can co-occur). Clinically, patients present with tender, erythematous cords along superficial veins that resolve and recur in different locations over time, sometimes preceding the cancer diagnosis by months. It is important to distinguish this from routine superficial thrombophlebitis unrelated to malignancy. Diagnostic workup in a patient with recurrent, migratory thrombophlebitis without clear risk factors should prompt malignancy screening, particularly for pancreatic cancer (checking CA 19-9, imaging). Management includes treating the underlying cancer and anticoagulation, typically with low molecular weight heparin (preferred over warfarin due to relative resistance and improved efficacy in cancer-associated thrombosis). This condition is a classic USMLE association: 'migratory thrombophlebitis + pancreatic cancer = Trousseau syndrome.' It also exemplifies a paraneoplastic syndrome mediated by tumor secretory products rather than direct tumor invasion.