Superficial thrombophlebitis of the chest wall usually presents as a subcutaneous cord 3 to 5 mm. in diameter aligned between the anterior axillary line or breast and the lower costal margin or umbilicus. In the past it has been confused with lymphatic spread of carcinoma, especially when involving the breast. This clinical and pathologic study of 7 patients supports the concept that the condition may be related to mechanical injury from effort or trauma. The data confirm reports of previous investigations that the lesion is benign and does not connote systemic disease or cancer.