RESUMO
We report a case of a 69-year-old woman with pleural mesothelioma presenting in the posterior mediastinum with a maximum diameter of 25 cm. She had a chronic cough and a pleural effusion was noted on chest X-ray. The examination of the effusion showed high hyaluronic acid levels, and mesothelioma was suspected. A chest computed tomography scan showed a huge mediastinal mass, which caused rapid progression of respiratory failure and compression of the heart. Sufficient tissue samples could not be obtained before death. The patient died approximately 1 month after the initial visit, and a pathological autopsy was performed. The diagnosis of malignant pleural mesothelioma was made. Malignant pleural mesothelioma with a huge posterior mediastinal mass such as in this case is considerably rare; however, it is a rapidly progressing form of the disease and is reported here as an important differential diagnosis for mediastinal tumours.