Thickening of the posterior tracheal stripe: a sign of squamous cell carcinoma of the esophagus.

A thickened posterior tracheal stripe (wider than 4.5 mm) was identified on the lateral check radiographs of 20 patients with squamous cell carcinoma of the esophagus. Autopsy studies confirmed that peri-esophageal lymphatic involvement was responsible for the thickening of the stripe in the nonobstructed esophagus. This sign appeared on the lateral chest radiograph as early as 6 months prior to the development of symptoms in 50% of the cases studied.