Many clinicians have had occasion to observe that patients who have carcinoma involving an internal organ are prone to develop thrombophlebitis in one or more superficial veins. Trousseau* first wrote about this observation 94 years ago. In brief, he stated that, if the diagnosis of a suspected carcinoma of an internal organ could not be verified, the sudden and spontaneous appearance of thrombophlebitis in a larger vein afforded necessary proof for diagnosis. Trousseau's basic observation stands, but in the light of our present knowledge certain other facts may be added to his statement. For example, the appearance of one or more lesions of thrombophlebitis may be the first tangible evidence of the presence of a visceral carcinoma. It is, therefore, the obligation of the clinician to classify as accurately and as early as possible any type of thrombotic lesion encountered.
There are two types of thrombotic lesions whicharecarcinogenetic in origin.