Indeed this is a case of tracheal "pleomorphic adenoma". Thanks for participation!

• Common tumor in an uncommon location can be difficult on frozen section.
• Identify components of 两型细胞: epithelial (tubule formation) and myoepithelial cells are critical.
• Of course myxoid or chondromyxoid stroma are very helpful the diagnosis.
• Epithelial compoment can have squamous metaplasia - can be mistaken for squamous cell carcinoma.

-------------------------------------------------------------------------------------------------------------------------------------------

Please share your interesting frozen cases.