Solitary fibrous tumour is a rare mesenchymal tumour of uncertain origin that occurs most frequently in the pleura, although it has also been described in extraserosal sites. The biological behaviour of the tumour is unpredictable. The case history is described of a patient diagnosed with a large symptomatic irresectable mediastinal solitary fibrous tumour who achieved a clinical, radiological and metabolic response after concurrent chemotherapy and radiotherapy.