Lame dog

Ebony is a 10 year old Female spayed Labrador dog who presented with a severe, sudden lameness of the left pelvic limb after jumping from a small wall in the garden.

A single lateral projection of the left crus is available for interpretation.

1. What radiographic signs are present?

2. What is your diagnosis?

3. List your differentials, in order.

4. Are there any other tests that you would recommend?

   

 

 

Answers

1. In the mid-diaphysis of the tibia there is a short oblique fracture with mild caudal displacement of the distal segment. The fracture margins are jagged, sharp and well defined. At the fracture margins there is a small amount of smooth, solid periosteal new bone ~2-3 mm high. The entire diaphysis, and the distal metaphysis and epiphysis is affected by permeative lysis, and cortical lysis, most severe in the distal third of the diaphysis and the distal metaphysis. In addition to this there is poorly mineralized spiculated periosteal new bone at intervals along the cranial and caudal tibial cortices. The zone of transition is long. Centred on the tibiotarsal joint there is moderate soft tissue swelling. There is a bandage present surrounding the limb.

2. Aggressive lytic bone disease of the tibia and tarsocrural joint, with a pathologic fracture in the left mid -diaphysis of the tibia.

3. This bone lesion is most likely to be a metastatic bone neoplasm (eg histiocytic sarcoma, haemangiosarcoma, fibrosarcoma, carcinoma), because of its mid-diaphyseal location. Primary bone neoplasia (osteosarcoma, histiocytic sarcoma) or fungal disease (aspergillus spp) are less likely in this location.

4. Given a metastatic bone tumour is suspected, more widespread imaging (eg of the thoracic and abdominal and pelvic cavities) is indicated. This could be achieved with radiography and ultrasound; alternatively CT or possibly scintigraphy may be very useful tests for screening large areas of the body.

Case courtesy of Dr Mika Frances, Veterinary Imaging Centre, Perth Veterinary Specialists, 2010.

 

 


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