Middle lobe syndrome: an intriguing presentation of tracheobronchial amyloidosis.

Pulmonary involvement in amyloidosis is a distinct rarity. This clinical entity usually presents as tracheobronchial amyloidosis (TBA). A 32-year-old, never-smoker man presented with episodic dyspnoea and wheezing along with cough and mucoid sputum. The chest radiograph was suggestive of a middle lobe syndrome (MLS). High-resolution CT (HRCT) of the chest confirmed the presence of MLS. In addition, HRCT showed circumferential thickening of the trachea and the main bronchi, with thickening of the posterior membranous wall of trachea. Fibrebronchoscopy, done to evaluate MLS, visualised multiple small polypoidal lesions in the lower part of trachea and carina. Endobronchial biopsies showed homogeneous, acellular amorphous deposit in the subepithelial region, which was congophilic in nature. A diagnosis of TBA presenting as MLS was made. To the best of our knowledge, this is the first detailed report of MLS as a presentation of TBA in the English literature.