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Thoracic Lung Mass Vs. Thymoma In An 11.5-Year-Old MN Shar Pei Mixed Breed: Our Case Of the Month June 2017

Patient Information

11 Years
Male, Neutered


Left side: Lung mass and adjacent hyperechoic area representing regional inflammation
Left side: Lung mass, impingement on right atrium and pericardium
Left side: Mass enveloping aorta.
FNA of lung mass; arrow pointing to needle track
VD Thoracic radiograph showing left sided thoracic mass.
LAT thoracic radiograph showing mass.

SDEP-certified clinical sonographer Amanda Lacey of Animal Sounds NW demonstrates that a mediastinal mass by any other still a mass that needs a needle. In this case the mass was easily visualized, it was confirmed that the area to FNA was avascular, a clear distance from the heart, and achieved intercostally, just as one would a liver FNA. 


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.

Image Interpretation

Left thorax in this patient reveals a lung consolidation with air entrapment. Regional inflammatory pattern is noted. The mass impinges upon the right atrium and pericardium. The mass appears to envelop the aorta  rendering resection difficult; however, debulking effort may prove somewhat fruitful depending upon cytology results. Minor potential for thymoma since it appears that air is present within the mass itself which would suggest origin. Minor mitral valve thickening was noted. Normal echocardiogram otherwise.

Sonographic Differential Diagnosis

Left cranial thoracic mass. Echotexture likely lung origin, less likely thymoma or ectopic thyroid carcinoma.


U/S-guided FNA of thoracic mass was performed without complication.


Cytology is consistent with a pulmonary adenocarcinoma.


Given the rapport with the aorta and other regional vasculature, resection will likely be difficult. However, CT evaluation would be ideal in this case for potential surgical planning depending on cytology results. Lung carcinoma or possible thymoma are primary differentials. If lung origin, differentials include lung carcinoma, lung sarcoma and lung necrosis. This may be thymic in origin. Radiology review of the radiographs would be ideal with oncology consultation if neoplasia is confirmed on the surgical and/or oncology consultation depending upon cytology results. Pathology found cells consistent with a pulmonary adenocarcinoma. The owners declined pursuing any type of surgical approach, have placed the dog on NSAID’s and is living comfortably at this time.


Many thanks to Amanda Lacey of Animal Sounds Northwest for her stellar imaging and FNA skills on this patient.

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Lung mass with minimal vascularity
Lung mass prior to FNA, showing minimal vascularity
FNA of lung mass, right down the barrel