Synovial osteochondroma involving the elbow of a cat.

CLINICAL PRESENTATION: A 12-year-old spayed domestic crossbred cat presented because she would not walk down stairs. A firm swelling on the medial aspect of the elbow was detected during physical examination. The lesion was not hot or painful on palpation and the lameness was mild, but the elbow had a reduced range of motion compared with the contralateral limb. DIAGNOSIS AND TREATMENT: Plain radiographs, physical findings, the appearance of the lesion at surgery and histopathological examination of biopsy specimens suggested the mass was a synovial osteochondroma arising from synovial membrane near the medial portion of the elbow joint. Resection of the lesion improved the cat's mobility and overall clinical status. At the time of writing, the cat continued to do well 18 months following surgery and was receiving standard doses of meloxicam for the concurrent elbow osteoarthritis. PRACTICAL RELEVANCE: Practitioners should be alert to the possibility of this benign entity. Misdiagnosis as a chondrosarcoma, for example, might conceivably lead to radical and unnecessary amputation.

Ulnar metaphyseal osteochondrosis in seven captive bred cheetahs (Acinonyx jubatus).

Distal ulna metaphyseal osteochondrosis was identified in seven captive bred cheetahs raised in Australia between 1984 and 2005. The disorder was characterized by bilateral carpal valgus conformation. In the metaphyseal region of the distal ulnae, an osteolucent defect that appeared as a proximal extension of the lucent physis was identified radiographically between 6 and 10 months of age. Ulna ostectomy was done to correct the angular limb deformity. Histologically, changes were identified in the osteolucent lesion that resembled osteochondrosis. We propose that the condition is probably familial and/or dietary in origin.