Solide Raumforderung im vorderen Mediastinum

Summary A solid tumour in the anterior mediastinum A 71-year-old asthmatic presented with increasing shortness of breath, which was attributed to an acute asthma exacerbation and responded rapidly and completely to appropriate treatment. Chest x-ray revealed a left parahilar mass which was new compared to a film taken 2 years previously. Subsequent CT scan of the chest showed the mass to be a tumour measuring 7.8 x 5.6 cm, situated in the anterior mediastinum between the aortic arch and the pulmonary artery. Its density was reported to be that of a solid mass (mean density –2 Hounsfield units). Transthoracic ultrasound revealed the surprise finding of a cystic lesion, and transthoracic fine needle aspiration revealed clear acellular liquid. The lesion was removed surgically and histopathology established the diagnosis of a benign thymic cyst. Such cysts are rare; computed tomography may be misleading as a diagnostic tool, whereas ultrasound is more accurate in documenting the cystic nature of the process. Surgical excision is the treatment of choice to preclude malignant transformation. It also serves to avoid secondary complications due to compression of surrounding structures by further cystic growth.