Severe episodic dyspnoea and abnormal flow-volume loop. Extramedullary plasmacytoma (EMP).

This case describes an extremely rare condition of extramedullary plasmacytoma (EMP) hidden in the middle media-stinum, giving no systemic signs but causing severe central airway narrowing detectable by the pattern of the flow-volume loop. The constant expiratory and inspiratory flow limitation is consistent with severe fixed narrowing of the central airway.1 Accurate analysis of the flow-volume curve pattern at the onset of symptoms would have given rise to a suspicion of tracheal compression several months earlier.