Case report: poorly differentiated carcinoma of unknown primary presenting as Trousseau's syndrome.

Two patients without clinical evidence of malignancy had idiopathic migratory thrombophlebitis. A clinical state consistent with Trousseau's syndrome prompted a work-up of each patient for occult cancer. In both individuals, computed tomography of the chest revealed a solitary mediastinal lymph node that, though inconspicuous, was evaluated further because of the clinical picture. Mediastinoscopy with biopsy revealed poorly differentiated carcinoma. Treatment was begun for carcinoma of unknown primary with variable response to therapy. The clinical presentation and pathophysiology of Trousseau's syndrome, as well as its use in leading to an antemortem diagnosis of occult cancer in these and other patients, are delineated.