Malignant mesothelioma with unexpected contralateral mediastinal shift: a case report

INTRODUCTION: Contralateral mediastinal shift due to pleural mesothelioma tissue, rather than a pleural effusion, is an unusual clinical feature of mesothelioma. CASE PRESENTATION: A 63-year-old woman with a past history of treated invasive ductal carcinoma of the breast presented with breathlessness and chest pain. Her chest radiograph revealed contralateral mediastinal shift and drainage of over 3 litres of pleural fluid relieved her symptoms. She underwent further investigations which revealed pleural mesothelioma, rather than the expected metastatic breast cancer. When she represented with breathlessness a few months later, a chest radiograph again demonstrated contralateral mediastinal shift. A thoracic ultrasound on this occasion revealed only a small loculated pleural effusion and, unexpectedly, a large volume of malignant tissue, thereby explaining the chest radiograph appearances. CONCLUSION: This case illustrates mediastinal shift away from the affected side which was caused by mesothelioma tissue itself, rather than by a pleural effusion which is the more usual cause of contralateral mediastinal shift in mesothelioma.