On the nature of peculiar expectorated bronchial casts: Can infrared spectroscopy enlighten us?

Background: Bronchial casts can be defined as gelatinous structures originating from the airways. While several cases of bronchial cast formation have been reported in literature, unravelling its nature is often a difficult task.

Methods: In this case report, we applied infrared (IR) spectroscopy on a bronchial cast fragment originating from a patient who suffered from a 2-y history of frequent coughing accompanied by the occasional expectoration of viscous and thick white-yellow bronchial-like structures.