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.