Tracheal Neoplasms



Tracheal Neoplasms


Jud W. Gurney, MD, FACR





Key Facts


Terminology



  • Rare malignant (90%) neoplasms of chest (0.1%), 2/3 either squamous cell carcinoma or adenoid cystic carcinoma


Imaging Findings



  • Proximal 1/2 of trachea: Adenoid cystic carcinoma


  • Lower 1/3 of trachea: Squamous cell carcinoma


  • Usually < 2.5 cm in size (otherwise would completely occlude trachea)


  • Tracheal lesions often overlooked (sensitivity 25-50%) on chest radiographs


  • Calcification in tumor not benign finding; seen in chondrosarcoma, carcinoid, mucoepidermoid carcinoma


Top Differential Diagnoses



  • Wegener Granulomatosis


  • Amyloidosis


  • Relapsing Polychondritis


Pathology



  • Top 5 (90% of tracheal tumors): Squamous cell carcinoma, adenoid cystic carcinoma, carcinoid, squamous cell papilloma, mucoepidermoid carcinoma


Diagnostic Checklist



  • Consider



    • Tracheal tumors in any patient with shortness of breath unresponsive to bronchodilators


    • Tracheal tumors if patient has dyspnea at night


  • Synchronous or metachronous 2nd primaries common (up to 40%)







Axial CECT shows a lobulated homogeneous mass involving the posterior tracheal wall image in this patient with squamous cell carcinoma.






Coronal CECT shows diffuse tracheal wall thickening image in a patient with adenoid cystic carcinoma. The longitudinal extent of the tumor exceeds the axial extent.


TERMINOLOGY


Definitions



  • Rare malignant (90%) neoplasms of chest (0.1%), 2/3 either squamous cell carcinoma or adenoid cystic carcinoma


IMAGING FINDINGS


General Features



  • Patient position/location



    • Proximal 1/2 of trachea: Adenoid cystic carcinoma


    • Lower 1/3 of trachea: Squamous cell carcinoma


  • Size: Usually < 2.5 cm (otherwise would completely occlude trachea)


Imaging Recommendations



  • Best imaging tool: CT method of choice to characterize extent of tumor


CT Findings



  • General findings similar in all intratracheal tumors


  • Factors favoring malignancy



    • Extraluminal extension


    • Circumferential involvement


    • Lobulated or irregular margin


    • Contrast enhancement with intravenous contrast


  • Factors favoring benignancy



    • Sessile or polypoid


    • Intraluminal only


    • Smooth and sharply marginated


  • Squamous cell carcinoma and adenoid cystic carcinoma have similar features, helpful distinguishing features



    • Squamous cell may be multifocal (10%)


    • Squamous cell more common to have regional lymph node enlargement


    • Adenoid cystic longitudinal extent > transaxial extent and tumor usually more than 180° of airway circumference


  • Fat content suggests lipoma or hamartoma


  • Calcification in tumor not benign finding; seen with chondrosarcoma, carcinoid, mucoepidermoid carcinoma


Radiographic Findings



  • Radiography




    • Tracheal lesions often overlooked (sensitivity 25-50%): Trachea common radiographic “blind spot”


    • Lungs usually normal, even when trachea nearly occluded


  • Patterns



    • Intraluminal (40%)



      • Apex to base tumor ratio > 1


      • Margin usually smooth


    • Wall-thickening (50%)



      • Apex to base tumor ratio < 1


      • Spindle-shaped


      • Margin usually smooth


    • Exophytic (10%)



      • Mediastinal widening


DIFFERENTIAL DIAGNOSIS


Wegener Granulomatosis



  • Vasculitis triad: Sinus, lung, renal disease


  • Cavitary nodules


  • Subglottic stenosis


  • Does not spare posterior tracheal membrane


Amyloidosis



  • Tracheobronchial most common form of amyloidosis


  • Nodular or diffuse deposits in airway wall, when diffuse involves entire wall


  • 30% calcify


  • Does not spare posterior tracheal membrane


Laryngotracheal Papillomatosis



  • Human papilloma virus


  • Multiple solid or cystic pulmonary nodules


  • At risk to develop squamous cell carcinoma (2%)


  • Does not spare posterior tracheal membrane


Tracheopathia Osteochondroplastica



  • Enchondrosis of cartilaginous rings


  • Usually small, do not compromise tracheal lumen


  • Spares posterior tracheal membrane


Relapsing Polychondritis



  • Autoimmune disorder destroys cartilage (airway, ear, nose)


  • Spares posterior tracheal membrane


PATHOLOGY


General Features

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Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Tracheal Neoplasms

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