Nasal congestion

An 11.5-year-old, 67.5 lb, MN, Shar Pei mixed breed dog was presented for chronic nasal discharge that was unresponsive to doxycycline and getting slowly worse. He started having mild congestion 3 months prior. He had enlarged submandibular lymph nodes then, which have since resolved. Hx of chronic conjunctival chemosis and elevated third eyelids. Medications: None. Radiograph Findings:  Mass effect in left side cranial thorax. CBC/chem/T4/UA were unremarkable.