Figure 3. a–c.

Missed lung cancer in a 75-year-old man who underwent chest X-ray after pacemaker positioning. A left iatrogenic pneumothorax was reported (a). An oval opacity in the posterior segment of the right upper lobe (arrows) was not identified by the radiologist (a, b). In the PA projection (a) the opacity was missed because of the superimposition with the fifth posterior rib arch crossing the first costo-sternal joint. In the lateral projection (b), the opacity was hidden by the upper thoracic vertebral bodies. CT performed a few days later (c) to rule out a pulmonary embolism, clearly depicted a soft tissue mass in the right upper lobe adjacent to the posterior mediastinal pleura.