He goes to work with me every day, where he acts as a therapy
dog for my (human) patients. He is a cheerful, gentle, playful, friendly
dog who easily wins people's hearts. He seems to work especially well with anxious people - his presence calms them.
I hope and pray that he does not have lymphoma or any other cancer. What is the differential diagnosis for a canine mediastinal mass - probably an enlarged lymph node?