The radiological features of osteosarcoma of the appendicular skeleton in dogs: a review of 74 cases

The clinical features, sites of origin and radiological changes associated with 75 osteosarcomas of the appendicular skeleton in 74 dogs are reviewed. Clinical data and the areas affected were broadly similar to those in previously reported series of cases, but the precise sites of origin were found to vary considerably from the generally accepted predeliction site, which is the metaphysis. A wide spectrum of radiological changes was recorded. Only 61.3 per cent of tumours could be classified as characteristic. A further 21.3 per cent showed features suggestive of, but not specific for, osteosarcoma and were therefore classified as equivocal. In the remaining 17.3 per cent the radiological signs, although indicative of neoplasia and usually of malignancy, were quite uncharacteristic. Among 63 cases in which both radiographic and post-mortem examination of the lungs was performed the incidence of pulmonary metastases was 13 per cent, with total correlation between their radiological and pathological detection. Of ten dogs which were treated surgically, one with a radiographically atypical lesion has survived for more than four years.