Glenoid dysplasia and osteochondritis dissecans in a cat

A 2-year-old Maine coon cat was presented for a right forelimb lameness. Computed tomography of the shoulder revealed a shallow glenoid, osteophyte deposition at the caudal humeral head and medial glenoid, and an intra-articular osseous body. This cat had glenoid dysplasia and osteochondritis dissecans of the glenoid.     

Hypertrophic osteopathy in a dog with a chronic lung abscess

A 2-year-old dog was examined because of gradual lameness of all 4 limbs and weight loss. Hypertrophic osteopathy was diagnosed. Radiography revealed a mass in the caudal lobe of the right lung. At necropsy, the mass was determined to be a chronic abscess. Corynebacterium pyogenes was cultured from the lesion. Although hypertrophic osteopathy in dogs is commonly associated with a thoracic lesion, most often neoplastic, the chronic lung abscess in this dog might have been formed as a result of a paralaryngeal abscess that was treated 3 months before the onset of the lameness.     

Osteochondral autograft transfer for treatment of osteochondritis dissecans of the caudocentral humeral head in dogs

Objective: To establish whether osteochondral autograft transfer (OAT) procedures for osteochondritis dissecans (OCD) of the canine caudocentral humeral head would restore articular contour, resurface osteochondral defects, and resolve lameness in dogs with OCD. Study Design: Case series. Animals: Dogs (n=14) with caudocentral humeral head OCD (16 shoulders). Methods: After arthroscopic assessment, the humeral head was exposed by arthrotomy. The OCD lesion was debrided and OATS^? instrumentation used for resurfacing the defect with osteochondral core grafts collected from the stifle. Recipient sockets were created to maximally resurface articular lesions. Outcomes measures included clinical, radiographic, and arthroscopic examination at 12–18 weeks and clinical examination at 12–46 months (mean, 30.8 months) postoperatively. Results: Resurfacing of the humeral head was achieved in all dogs. Subjectively, lameness resolved in 9 of 16 limbs by 5–6 weeks postoperatively, and in 13 limbs by 12–18 weeks. Radiographically, all autografts were maintained. On second‐look arthroscopy, the grafted section was intact, resilient on probing, satisfactorily conformed to the adjacent articular contour, and grossly appeared consistent with hyaline or fibrocartilage depending on the graft source. Of 12 limbs available for 12–46 months reevaluation, none were considered lame and mild discomfort on shoulder manipulation was recorded for only 1 joint. Conclusions: OAT procedures are technically feasible in the caudocentral aspect of the canine humeral head. Articular contour reconstruction, resurfacing of osteochondral defects, and amelioration or resolution of short‐term lameness may be achieved.     

OSTEOSARCOMA WITH A PATHOLOGIC FRACTURE IN A SIX-MONTH-OLD DOG

This case history report describes the clinical, radiographic, and histopathologic features of an osteosarcoma with an associated pathologic fracture in a 6-month-old dog. A 6-month-old intact male Bloodhound was presented with a primary complaint of a right forelimb lameness of one month's duration. In radiographs, a minimally displaced transverse fracture of the proximal humeral metaphysis was seen. There was extensive cortical bone destruction at the fracture site and minimal periosteal new bone suggestive of a primary bone tumor with a pathologic fracture. Biopsy specimens demonstrated neoplastic mesenchymal cells producing osteoid compatible with a diagnosis of osteosarcoma. This case history report constitutes the youngest reported canine osteosarcoma.     

OSTEOSARCOMA OF THE PATELLA WITH PULMONARY METASTASES IN A DOG

A 6-year-old neutered male Rottweiler was examined for a progressive right pelvic limb lameness. In radiographs of the right stifle, there was an osteolytic lesion with irregular new bone formation along the cranial aspect of the patella consistent with an aggressive bone lesion. In thoracic radiographs, there were multiple soft tissue nodular opacities throughout the lung fields, consistent with pulmonary metastases. Microscopically, fine needle aspirate samples from the right patella contained pleomorphic spindle cells with cytologic features of osteosarcoma. The presence of pulmonary metastases at the time of initial diagnosis in the dog described herein suggests that osteosarcoma of the patella has the potential for similar aggressive biologic behavior as that seen in dogs with appendicular osteosarcoma.     

Traumatic craniolateral shoulder luxation and fracture of the lesser tubercle of the humerus in a dog

A five-year old, spayed female, Bearded Collie was presented with a 24-hour history of non-weight-bearing lameness of the right thoracic limb after sustaining vehicular trauma. Radiographs revealed a craniolateral scapulohumeral luxation and a distally and medially displaced fracture of the lesser tubercle of the humerus. Open reduction and internal fixation of the fracture was achieved with lag screw fixation and an anti-rotational Kirschner wire. Surgical repair resulted in compression across the fracture line, anatomic reduction of the articular surface, and a stable scapulohumeral joint following reduction of the humeral head in the glenoid. Six weeks postoperatively, the patient exhibited no evidence of pain or lameness on the right thoracic limb and radiographs revealed complete healing of the fracture and normal articulation of the scapulohumeral joint. This is the first report of a lesser tubercle fracture associated with a craniolateral shoulder luxation. Surgical intervention resulted in the return of full shoulder joint function in this dog.     

Mid-to-caudal partial hemipelvectomy with limb preservation for ischial tumor in a dog

A 10-year-old spayed female Golden Retriever was referred for hindlimb lameness. A firm mass was palpated over the right caudal pelvis. Computed tomography revealed an osteolytic bone region and an associated periosteal reaction in the ischium, including the acetabulum. The histological diagnosis was sarcoma of unknown origin. A mid-to-caudal partial hemipelvectomy was performed to remove the mass. Femoral head and neck osteotomy was performed to allow hindlimb preservation. Following surgery, the dog regained satisfactory hindlimb use over time and was alive for 821 days with no recurrence or metastatic disease. This report indicates that mid-to-caudal partial hemipelvectomy with femoral head and neck osteotomy is technically feasible and allows for tumor control with preservation of the hindlimb and its function.     

Propagation of a partial incomplete ossification of the humeral condyle in an American cocker spaniel

A hypoattenuating lesion in the left humeral condyle of an American cocker spaniel consistent with partial incomplete ossification of the humeral condyle was observed on computed tomography. Left forelimb lameness developed over the following three weeks at which time repeat computed tomography examination confirmed propagation of the lesion. Lameness resolved following placement of a transcondylar positional screw, suggesting that lameness was secondary to condylar instability. To the authors' knowledge this is the first report of propagation of an intracondylar lesion in a dog.     

Premature closure of the proximal physis of the humerus in a dog as a result of harvesting a cancellous bone graft

A 5-month-old castrated male mixed-breed dog was evaluated because of lameness of the right forelimb. Physical examination revealed pain on manipulation of the right elbow joint, and radiography revealed premature closure of the distal physis of the radius with subluxation of the right elbow joint. Corrective osteotomy of the radius was performed to increase the length of the radius and establish congruity of the elbow joint. Cancellous bone was obtained from the proximal portion of the humerus and used as a graft at the osteotomy site. The dog did well after surgery. Four months after surgery, the dog again was lame on the right forelimb. Physical examination revealed instability of the right shoulder, and manipulation of that area elicited signs of pain. Radiography revealed caudomedial subluxation of the right shoulder as well as deformity of the humeral head and hypoplasia of the greater tubercle. It was presumed that these changes were associated with collection of the cancellous bone graft during the initial surgery, which resulted in premature closure of the proximal physis of the humerus. To our knowledge, this is the first report of premature closure of the proximal physis of the humerus as a result of procurement of a bone graft.     

Metastatic transitional cell carcinoma in proximal humerus of a dog

Transitional cell carcinoma (TCC) was diagnosed in the proximal humerus of a dog that was presented with persistent right forelimb lameness with no clinical signs of urinary tract involvement. A diagnosis of TCC was made from surgical biopsy of the humeral lesion with subsequent necropsy revealing the prostatic urethra as the primary site of the tumor.     

Osteochondritis dissecans of the humeral head of a cat

A one-year-neutered male cat was presented for veterinary examination because of a left forlimb lameness. A painful left shoulder joint was found on examination and radiology of this joint revealed an erosive lesion of the humeral head and a detached flap of articular cartilage. The detached cartilage was surgically removed after which the lameness resolved. The lesion in this cat resembled osteochondritis dessicans of other species but whether the pathogenesis of the condition in this cat was 115 similar also was not determined.     

Zoledronic acid for the treatment of appendicular osteosarcoma in a dog

A 10-year-old male intact Corso dog was referred for lameness and for a large neoplasm affecting the right foreleg. Physical examination of the patient revealed a 5 × 5 × 3 cm mass in the distal right foreleg. Histopathology was consistent with a diagnosis of appendicular osteosarcoma. The staging process found no evidence of metastasis. Because of the large size of the patient, the owners elected to treat their dog with antiresorptive therapy. The patient was treated with an infusion of zoledronic acid every 28 days. The tumour remained stable for 16 months and the lameness of the dog greatly improved. At that time, the patient returned for evaluation of a large rapidly growing prescapular mass. Biopsy confirmed lymph node metastasis and the dog was euthanased. Zoledronic acid showed remarkable palliation in our patient and possibly anti-tumour action and warrants further investigation.     

IMAGING DIAGNOSIS—NUCLEAR SCINTIGRAPHIC,RADIOLOGICAL, AND PATHOLOGIC CHARACTERISTICS OF METASTATIC PILOMATRICOMA IN A DOG

A 6‐year‐old castrated Goldendoodle dog was presented for left‐sided lameness of 3 weeks’ duration. Focal, moderate to marked increased ^99mTc‐methylene diphosphonate (^99mTc‐MDP) uptake was detected in the right caudal lung lobe, caudal angle of the left scapula, and the distal aspect of the left femur with whole body bone phase scintigraphy. Radiographs identified a well‐circumscribed, oval‐shaped soft tissue opaque mass in the right caudal lung lobe; a suspect oval‐shaped osteolytic lesion in the proximal third of the left scapula; and an osteolytic lesion in the distal aspect of the left femur. Metastatic pilomatricoma was confirmed histologically at all three sites.     

Osteosarcoma at the site of a triple pelvic osteotomy in a dog

An osteosarcoma (OSA) involving the right pelvis was diagnosed in a 12-year-old golden retriever 11 years after triple pelvic osteotomy (TPO) surgery. The dog was presented with a 12-week history of nonweight-bearing lameness of the right hind limb. Radiographs demonstrated an aggressive bone lesion of the right ilium with profound periosteal proliferation and punctate lysis that extended along the ilium caudally and into the right ischium, with its epicenter at the level of the right TPO plate. Necropsy revealed that the entire right hemipelvis, especially the ischium, was markedly thickened and firm with irregular margins. Histopathology was consistent with a diagnosis of OSA.     

Osteosarcoma in the proximal humerus of a mare

A 15‐year‐old Quarter Horse mare was examined for significant and progressive lameness in the right front limb. On physical examination, muscle atrophy over the scapular and pectoral regions were noted. A pain response was elicited on palpation of the scapulohumeral joint. No other abnormalities were noted on examination of the limb. Diagnostic nerve blocks ruled out a source of lameness in the distal limb. Arthrocentesis of the scapulohumeral joint was performed and results were within normal limits. Radiographs of the right scapulohumeral joint revealed an extensive, aggressive bone lesion in the proximal humerus, suspected to be an osteosarcoma. After a course of nonsteroidal anti‐inflammatory therapy, minimal improvement to the lameness was noted. The owner elected to subject the horse to euthanasia due to the lack of significant response to treatment. Post mortem radiographic and histological examinations determined a definitive diagnosis of an osteosarcoma in the proximal humerus.     

Aneurysmal bone cyst in a six-month-old dog.

A 6-month-old female Yorkshire Terrier was examined because of acute left forelimb lameness secondary to a Salter-Harris type IV fracture of the lateral condyle of the humerus. Radiography revealed an eccentric, osteolytic lesion in the distal humeral metaphysis associated with a pathologic fracture. The limb was amputated, and the dog recovered. Microscopic examination revealed an extensive zone of hemorrhage and dilated coalescent spaces, which were filled with blood. Hemosiderin-laden macrophages and multinucleated giant cells were observed throughout the stroma. On the basis of clinical, radiographic, and histologic examinations, a diagnosis of aneurysmal bone cyst was made. Aneurysmal bone cysts generally have been detected in 11- to 13-year-old, medium- to large-sized dogs. They can develop secondary to malignant processes.     

Osteochondritis dissecans-like lesion of the intercondylar fossa of the femur in a dog.

An 11-month-old neutered female crossbreed dog was admitted with left pelvic limb lameness. Radiographs and computed tomography identified an osteochondritis dissecans- (OCD) like lesion in the intercondylar fossa of the femur originating from the axial aspect of the medial femoral condyle. Stifle arthrotomy was performed in order to remove the bony fragment. It was concluded that the clinical features and location of this lesion indicate an osteochondritis dessicans-like lesion. Fragment removal was associated with an excellent outcome.     

Paraganglioma,pituitary adenoma,and osteosarcoma in a dog

An 11‐year‐old neutered male Alaskan Malamute mixed‐breed dog was presented with a complaint of polyuria/polydipsia (PU/PD), weight loss, tachypnea, regurgitation, and a previous history of nontreated osteosarcoma of the right distal radius, diagnosed 21 months prior. On physical examination, an abdominal mass was palpated. The abdominal mass was aspirated and cytologically diagnosed as a neuroendocrine tumor, suspected to be a pheochromocytoma. Laboratory examination revealed a mild anemia and thrombocytopenia, markedly elevated ATP and ALP activities, and moderate hypercalcemia. A low‐dose dexamethasone suppression test and endogenous adrenocorticotropic hormone (ACTH) concentration were compatible with pituitary hyperadrenocorticism. On urinalysis, proteinuria was noted as well as a high urine metanephrine/creatinine ratio, consistent with a diagnosis of pheochromocytoma. The dog was treated with supportive care and euthanized 6 months later due to decreasing quality of life. On necropsy, an extra‐adrenal pheochromocytoma (paraganglioma) was diagnosed in the caudal abdomen, and a pituitary adenoma and an osteosarcoma of the right distal radius were confirmed.     

Arthroscopic Surgical Approaches and Intraarticular Anatomy of the Equine Shoulder Joint

Arthroscopic approaches to the scapulohumeral joint were developed in four clinically normal, live horses (5 limbs) to determine their usefulness for evaluation and potential surgical treatment of intraarticular lesions. The articular surface of the entire glenoid, cranial humeral head (medial and lateral) and caudolateral humeral head, as well as the synovial membrane, could be closely examined from an arthroscopic portal cranial to the infraspinatus tendon. The caudomedial humeral head could be examined partially. Cranial and caudal instrument portals allowed good surgical access to the entire glenoid and the majority of the humeral head (except caudomedial in adult, heavily muscled horses). The described arthroscopic and instrument portals allowed access to the areas frequently affected with osteochondritis dissecans (OCD). Potential difficulties with this technique include problems establishing triangulation, extravasation of fluids, and inability to reach potential lesions on the caudomedial humeral head with conventional equipment in heavily muscled horses.     

Magnetic resonance imaging diagnosis: incomplete ossification of the humeral condyle in a German shepherd dog

Clinical signs, radiological, arthroscopic findings and magnetic resonance imaging features of a male German shepherd dog with incomplete ossification of the humeral condyle are described. The dog showed recurrent left forelimb lameness and pain on elbow palpation. In routine radiographs, the lesion was obscured. In oblique radiographs, a radiolucent line was detected, and magnetic resonance imaging clearly demonstrated a defect in the humeral condyle. However, arthroscopy showed no changes or discontinuity of the humeral cartilage. Incomplete ossification of the humeral condyle may be underrepresented in conventional, routine studies because if there is concurrent additional elbow pathology (for example fragmented coronoid process), treatment may lead to clinical improvement and further diagnostic techniques may not be performed. The benefit of magnetic resonance imaging in this case is demonstrated.