9. 38 year old never-smoking man with progressive shortness of breath with exercise, and wheezing on auscultation of the central chest.  Endoscopy showed an endoluminal tracheal mass 2 cm. above the carina, and tracheal resection was performed.
  

Diagnosis = Adenoid Cystic Carcinoma

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http://radiographics.rsna.org/content/31/5/1443.short