A thymoma can be suspected in a patient with myasthenia gravis or one of the other autoimmune or endocrine disorders noted above.

Imaging 
• A thymoma can be strongly suspected if a mass is seen on a chest x-ray in the location of the thymus in the
  center of the chest.

Endoscopy and Biopsy 
• The biopsy needed for a definite diagnosis may sometimes be obtainable with a fine needle aspiration (FNA) but
  may also require definitive surgery.