A seven-year old male, neutered Great Dane presented with a five-week history of left thoracic limb lameness.
fig. 1 - mediolateral radiograph of left elbow - reveals irregular bone loss within olecranon
fig. 2 - STIR MR-scan of elbow - high signal in region of olecranon reveals extent of tumour.
Examination revealed a firm, fixed, non-painful swelling medial to the left olecranon and resentment of flexion of the elbow. Radiology (fig. 1) revealed irregular loss of bone within the olecranon. Thoracic films were unremarkable. STIR-weighted MR-scans of the elbow revealed a focal area of bone inflammation consistent with neoplasia (figs. 2 & 3).
Impression smears from needle aspirates of the swelling were consistent with osteosarcoma, and the owner elected not to pursue further treatment.
fig.3 - dorsal (craniocaudal) STIR MR-scans of the elbow
This case illustrates the exception to the rule that such tumours usually occur ‘near to the stifle’ (distal femoral/ proximal tibial epiphyses) and ‘away from the elbow’ (proximal humeral/ distal radial epiphyses). It also illustrates the graphic appearance of metabolic bone changes on MR imaging.