Synovial osteochondromatosis and sclerosing osteosarcoma in a cat.

The clinical, radiographic and histological features of synovial osteochondromatosis in multiple joints and an unrelated sclerosing osteosarcoma of the left tibia in a cat are reported. Radiographic evaluation showed signs of several nodular radiopacities in both stifles and both shoulders. Pathologic transverse fractures of the left tibia and fibula were also present. A midfemoral amputation of the left hindlimb was performed and treatment consisted of lifelong administration of nonsteroidal anti-inflammatory drugs. Histological evaluation confirmed synovial osteochondromatosis of the left stifle and sclerosing osteosarcoma of the left tibia. This is the first report of a feline patient with bilateral synovial osteochondromatosis that describes the clinical, radiographic and histological aspects of this disease.

Primary synovial osteochondromatosis of the stifle in an English Mastiff.

A two-year-old, 97 kg, male neutered English Mastiff was evaluated for left pelvic limb lameness of five months duration localized to the stifle joint. Following radiographic, computed tomographic and arthroscopic examination, the lameness was subsequently diagnosed as being caused by primary synovial osteochondromatosis. In total, 194 osteochondral bodies were removed using arthroscopy in combination with a mini-arthrotomy. Histology and immunohistochemistry of the loose osteochondral fragments confirmed the diagnosis with a moderately high degree of differentiation and low cellularity. Nuclear staining for Ki-67 revealed decreasing differentiation and increasing cellularity in the fragments. At the 13 months telephone follow-up the owner reported that the dog was free from lameness and had a vastly improved function compared with preoperative levels, although mild lameness did occasionally occur. This is the first report of computed tomography, arthroscopy and immunohistochemistry confirming a case of primary synovial osteochondromatosis in a dog.

Synovial osteochondromatosis with malignant transformation to chondrosarcoma in a dog.

A 4.5-year-old intact male Labrador Retriever dog had a 1-month history of right forelimb lameness with painful swelling of the elbow. The radiographic findings of increased synovial mass with mineralized opacities and the gross and histologic findings in the synovial biopsy specimens were consistent with a diagnosis of primary (idiopathic) synovial osteochondromatosis. Twenty months after initial presentation, based on progression of clinical signs and radiographic evidence of marked bone lysis in the distal aspect of the humerus and proximal aspects of the radius and ulna, the affected leg was amputated. The histologic diagnosis was chondrosarcoma with fibroblastic differentiation and bone lysis. The chondrosarcoma was interpreted as malignant transformation of primary synovial osteochondromatosis.

Extra- and intra-articular synovial chondromatosis and malignant transformation to chondrosarcoma.

Intra- and extra-articular primary synovial chondromatosis (SC) was observed in a five-year-old, entire male German Shepherd. Thousands of small cartilaginous nodules were removed from the stifle joint as well as from several adjacent muscles. Diagnosis of SC was established based on clinical, radiographic and biopsy results. The owner declined to have a new surgery performed for complete nodule removal and partial synovectomy. Nine months after the initial presentation, a proximal pathological intra- articular tibial fracture was observed and malignant transformation to chondrosarcoma was diagnosed after limb amputation. No metastasis was observed after 1.5 years of follow-up.

A review of lameness attributable to the shoulder in the dog: part two.

The scapulohumeral joint is a common site of forelimb lameness in the dog. Establishing a definitive diagnosis may be difficult because of the limitations of orthopedic examination and radiographs and the inherent elusiveness of the associated conditions. The intent of this review is to present, in a single reference, the pathophysiology, diagnosis, and treatment of reported causes of lameness intrinsically associated with the shoulder. Part One of this series discusses conditions associated with cartilage and bone maturation disorders and joint instability, while Part Two reviews tendon diseases, muscle disorders, synovial diseases, and soft-tissue mineralization disorders.

Synovial chondromatosis in raptors.

Fourteen raptors, consisting of 13 great horned owls (Bubo virginianus) and one red-tailed hawk (Buteo jamaicensis), from central and north central Minnesota, western Wisconsin, and eastern South Dakota (USA) were admitted to a raptor rehabilitation center between June 1992 and June 1995, with perisynovial and synovial chondromatosis affecting multiple joints. Birds were severely debilitated primarily due to loss of shoulder motion. The etiology of these lesions in raptors is unknown.

Arthrodesis of the shoulder for synovial osteochondromatosis.

A case of synovial osteochondromatosis (SOC) in a young deerhound's shoulder is reviewed. The age of onset and initially unaffected articular surfaces suggested primary SOC. Histological criteria for primary versus secondary osteochondromatosis are contradictory and unclear. Initial loose body removal and partial synovectomy resulted in several months of improvement but loose bodies returned. Severe degenerative changes were found one year after the initial exploratory surgery. Arthrodesis resulted in a functional, non-painful joint.

Synovial chondromatosis in a great horned owl (Bubo virginianus).

A case of synovial chondromatosis in a great horned owl (Bubo virginianus) was found in June 1993. In radiographs of bilateral swelling of the scapulohumeral joint we observed numerous mineralized foci in the soft tissue. The foci were identified by light microscopy as cartilaginous metaplasia. This is the first report of synovial chondromatosis in an owl.