Today’s case is a 12-year-old female neutered Labrador Retriever with acute onset of lameness after chasing a ball. What is your diagnosis?
Right humerus: There is permeative lysis of the cranial and proximal diaphysis and metaphysis of the humerus. There is mild soft tissue swelling cranial to this region. Smooth periosteal reaction is visible on the caudal, medial, and lateral aspects of the humerus.
Thorax: The cardiac silhouette is normal in size and shape. There is a soft tissue nodule superimposed on the cardiac silhouette on the left lateral projection, located in the right middle lung lobe at the 5th intercostal space on the dorsoventral projection. There is a moderate bronchointerstitial pattern throughout the lungs. The mediastinum and pleural space are normal.
- Aggressive bone lesion in the right humerus, most likely a primary bone tumor
- Single pulmonary nodule, most likely metastatic disease.
Ultrasound fine needle aspirate of the humerus was performed. The cytological diagnosis was sarcoma, most likely osteosarcoma; however, hemangiosarcoma or histiocytic sarcoma could not be ruled out.