Chondrosarcoma in a cow.

Chondrosarcomas are rare in cattle and none has been described in detail. A 30 cm diameter chondrosarcoma centred upon the costochondral junctions of the left 9th to 12th ribs of a 5-year-old Aberdeen Angus cow is described. In areas with a cartilaginous matrix the chondrocytes were plump, sometimes binucleate, sometimes bizarre, with occasionally 2 or more cells per lacuna. The other major matrix was loose and fibrillar, and the cells were spindle-shaped or stellate, with a moderate mitotic rate. Small areas appeared fibrosarcomatous. Both major types of matrix were present in the metastases, which extensively involved the pleura, intrathoracic lymph nodes and lungs. Less numerous and smaller metastases were present on the peritoneal surfaces and within several abdominal and pelvic organs. It is postulated that local extension of the tumour from the primary mass was followed by lymphatic spread to the lungs.