A 9-year-old boy was referred to the Oncology Department because of a thoracic soft-tissue mass thought to be a chest wall tumour. He had a history of grass inflorescence (Hordeum murinum) aspiration 2 weeks prior to this admission. On physical examination a tender soft-tissue mass under the right scapula and diminished breath sounds from the right lower lobe were detected. Thoracic CT confirmed soft-tissue swelling of the right posterior chest wall. There was a hypodense area within the soft-tissue mass suggesting a foreign body and also focal consolidation of the right lower lobe adjacent to the soft-tissue swelling. We report here unique CT findings of grass inflorescence aspiration before and after its migration through the airways. © Springer-Verlag 2006.