Idiopathic mediastinal fibrosis is an occasionally observed disease of mostly unknown etiology characterised by slowly progressive fibrosis and exuberant collagen formation within the mediastinum. This can result in clinical syndromes causing extension to and compression of the mediastinal structures.In Europe, this disease is exceptionally rare. More cases are seen We present a young male patient who was at first thought to have pulmonary malignancy but later shown to have idiopathic mediastinal fibrosis after a five-year follow-up.