Plastic bronchitis (PB) is a rare disease caused by abnormal lymphatic vessels in the thorax. These vessels drain into the bronchi creating solid casts and potential life-threatening airway obstruction. This is a case report of a 30-year-old man diagnosed with PB after several years of extensive examinations due to symptoms misconceived as non-allergic asthma. We describe the first interventional treatment in Denmark using special T2 weighed MR imaging and dynamic contrast MR lymphangiography with subsequent embolisation of abnormal lymphatic vessels in the thorax.