This MRI is on a 11 year old shepherd mix dog who presented with lethary, hind leg weakness, loss of appetite, and a history of lipomas. A chest x-ray demonstrated a large dorsal mid thoracic mass. Respiratory gating was used to decrease the artifacts associated with the ventillation, allowing high quality detail of the chest and mid thoracic spine. MRI further diagnosed two more thoracic lesions to make a total of three; a large expansive mass left dorsal thorax, originating from the 5th rib, the second enhancing mass noted within the right cranial lung lobe, and a third nodule in the left cranial lung lobe. The most likely differential is primary neoplasia involving the left 5th rib head, in particular a sarcoma, with metastatic pulmonary neoplasia.