Today’s case is a 10-year-old male neutered American Eskimo dog presented for lameness in the left thoracic limb that has persisted for 2 months.
Radiographs: A single lateral projection of the left forelimb is available for review. There is geographic lysis involving the distal humerus, proximal ulna, and to a lesser degree of the proximal radius. The areas of bone loss are multifocal with relatively well circumscribed borders. The anconeal process is absent. There is a large soft tissue swelling centered around the left elbow.
Ultrasound: A very heterogeneous, hyperechoic lesion surrounding the caudal aspect of the elbow and also extending to medial and lateral is identified. There are severe defects within the bone and the mass lesion extends into the bone. Fine needle aspirates were taken without immediate complications.
Aggressive bony lesion with a large soft tissue component involving multiple bones centered at the left elbow. Malignant neoplasia is the primary differential, and considerations should include joint neoplasms such as histiocytic sarcoma or synovial cell sarcoma, as well as soft tissue neoplasm such as a soft tissue sarcoma. Ultrasound guided fine needle aspirate of these lesions is recommended.
Cytology: Mesenchymal proliferation and marked atypia with increased plasma cells and recent hemorrhage – probable sarcoma