Use of Enrofloxacin and Hydrotherapy in the Management of Fibrodysplasia Ossificans Progressiva (FOP) in a Savannah Cat.

FOP is a rare genetic condition, described mainly in man and cats, characterized by progressive, painful debilitation and shortened lifespan. A 10-month-old neutered male Savannah cat was referred for progressive gait abnormalities and multifocal firm masses within the soft-tissues that were unresponsive to previous treatment. Diagnosis of FOP was based on histopathological evaluation of intralesional biopsies, which revealed osteo-cartilaginous metaplasia and fibrocellular proliferation with intralesional chondrogenesis and endochondral ossification. The cat was managed with 5 mg/kg BID enrofloxacin and hydrotherapy for 3 years until acute death. During that three-year period, the cat displayed consistent improvement in endurance, quality of life, and range of motion. Postmortem histopathology further confirmed the diagnosis of FOP via identification of intramuscular and intra-fascial ossification with lymphoplasmacytic infiltration, degeneration, and regeneration of adjacent myocytes. To the authors' knowledge, this is the first report of long-term enrofloxacin treatment and hydrotherapy for the management of FOP in a cat, leading to improved mobility and survival time, and the first report of FOP in an exotic breed cat.

MYOSITIS OSSIFICANS TRAUMATICA IN A VAMPIRE BAT (DESMODUS ROTUNDUS).

A 15-yr-old sexually intact female vampire bat ( Desmodus rotundus ) was diagnosed with myositis ossificans traumatica of the abdominal wall. The bat presented with a large ulcerated firm mass along the abdomen. Radiographs and cytology were performed, followed by surgical exploration. The mass was determined to be nonresectable and the bat was euthanized. Histopathology showed severe necrotizing, degenerative, and pyogranulomatous myositis with osseous and cartilaginous metaplasia, fibrosis, and ulceration, which were consistent with myositis ossificans traumatica. Myositis ossificans traumatica is commonly associated with previous trauma to skeletal muscle. Two years prior, this bat had an emergency Caesarian section at this site, which was postulated to elicit a marked tissue response leading to this condition. Myositis ossificans traumatica is infrequently reported in humans, dogs, cats, pigs, and horses. To the author's knowledge, this is the first report of this condition in a bat.

Surgical Treatment of Traumatic Myositis Ossificans of the Extensor Carpi Radialis Muscle in a Dog.

OBJECTIVES: To report clinical signs, diagnostic imaging findings, and outcome in a dog with traumatic myositis ossificans of the origin of the extensor carpi radialis muscle. STUDY DESIGN: Clinical report. ANIMALS: An 8-month-old intact female Irish Setter Dog. METHODS: After radiographic and computed tomographic evaluation of an osseous proliferation arising from the cranial cortex of the right distal humeral diaphysis, the protruding bone was surgically removed and evaluated by histopathology. RESULTS: Traumatic myositis ossificans was successfully treated with surgical removal of the osseous proliferation resulting in improved postoperative range of motion of the right elbow joint. There was no evidence of lameness or abnormal bone regrowth associated with the surgical site radiographically at follow up. CONCLUSION: Surgical removal of a traumatic myositis ossificans lesion resulted in full return to function in a young, competitive show dog.

Imaging diagnosis: fibrodysplasia ossificans progressiva in a cat.

A 1-year-old female cat was presented for progressive alopecia, gait abnormalities, and stiffness. Radiography demonstrated multiple calcified lesions within the soft tissues of the cervical and thoracic spine, shoulder, and limbs. Postmortem computed tomography provided more detailed information on the distribution, pattern, and extension of lesions. In addition, computed tomography helped guide sample selection for histopathology. The final diagnosis was fibrodysplasia ossificans progressiva. This is a rare disorder of unknown etiology, characterized by fibrosis and heterotopic bone formation in connective tissues. To the authors' knowledge, this is the first report describing this disease in a European cat.

Myositis ossificans circumscripta of the triceps muscle in a Rottweiler dog.

A 20-month-old male Rottweiler dog was presented with the complaint of chronic right forelimb lameness that was unresponsive to conservative treatment. Physical examination allowed for the topographical identification of the source of the problem as a firm enlargement of the soft tissues that was partially movable from humeral bone and compatible with an alteration of the triceps brachii muscle. Radiographic images showed signs that were highly suggestive of myositis ossificans. Computed tomography allowed for a more accurate characterization of the lesion, to exclude involvement of the elbow joint and humeral bone, and to localize anatomically the lesion in the caput accessorium and longum of the triceps brachii muscle. Surgical excision of the ossified portion of the triceps muscle was performed. Histological examination of the excised tissue substantiated the diagnosis of myositis ossificans. A one year clinical and radiographic follow-up examination showed a complete recovery, with no evidence of complications or recurrence. Despite myositis ossificans in dogs having previously been identified in the hindlimbs, this case of myositis ossificans circumscripta of the triceps muscle suggests that it may also occur in the muscles of the forelimb.

Kinematic characteristics of myositis ossificans of the semimembranosus muscle in a dog.

A 6-year-old Doberman pinscher dog was presented with myositis ossificans of the semimembranosus muscle. Linear, temporal, and angular kinematic patterns were recorded and compared with those of sound dogs of the same breed. The results indicate that the specific gait compensations occurring with this disease may aid in the diagnosis of myositis ossificans of the caudal thigh muscles.

Fibrodysplasia ossificans progressiva in a Maine Coon cat with prominent ossification in dorsal muscle.

A one-year and six-month-old female Maine Coon cat presented with skin problems and paravertebral induration with a history of seven months. Survey radiographs and computed tomography revealed prominent calcifications in both sides of cervical, thoracic and lumbar vertebrae and soft tissue in femoral regions, below knee regions and in brachial regions. Histopathological findings from muscle biopsy samples showed connective tissue proliferation around adjacent skeletal muscle, cartilage formation and endochondral ossification. On the basis of these findings, this feline patient was diagnosed with fibrodysplasia ossificans progressiva (FOP). The most prominent signs observed in this FOP case were significant calcifications of dorsal muscle and presentation of cutaneous signs at the early stage.

Fibrodysplasia ossificans progressiva-like condition in a cat.

Fibrodysplasia ossificans progressiva (FOP)-like condition was diagnosed in a Japanese domestic cat with stiffness, marked atrophy of the muscles, and limited mobility of all joints in both the pelvic limbs. Etretinate, a retinoid, was used for medical management; however, no improvement in the clinical signs was observed. Inheritance of the disorder has not yet been demonstrated. Furthermore, the clinical signs and histopathological findings of feline FOP-like condition in the present case differed from those of the previously reported cases.

Fibrodysplasia ossificans in a German shepherd dog.

Bilateral cervical heterotopic ossification, associated with a thoracic limb lameness, occurred in an adult German shepherd dog. One of the lesions, thought to be the cause of the lameness, was surgically removed and the lameness resolved. The lesion was classified morphologically as fibrodysplasia ossificans. A similar, smaller lesion was present over the cranial distal scapular border. The causes of ectopic ossification, as described in the veterinary literature, are reviewed and compared with myositis ossificans in humans. Non-progressive fibrodysplasia ossificans has been described in cats, but this appears to be the first report in the dog. It is postulated that the heterotopic ossification resulted from the metaplastic change of calcinosis circumscripta lesions.

Fibrodysplasia ossificans progressiva in the cat. A case report.

Clinical, radiographic, electromyographic, and pathologic findings in a cat with fibrodysplasia ossificans progressiva are described. The features of five previously reported cases of this feline disorder are also presented. This disorder affects young adult to middle-aged cats of both sexes. Characteristic clinical features include progressive stiffness of gait, with enlargement of proximal limb musculature. Radiography reveals multiple mineralized densities within the affected musculature. The clinical course is rapid, with development of severe disability within 2 weeks to several months. Electromyographic and pathologic findings suggest that this is a disorder of connective tissue, affecting primarily the epimysium, tendons, and fasciae, and results in marked proliferation of fibrovascular connective tissue, with associated chondroid and osseous metaplasia.

Progressive ossifying myositis in a cat.

Progressive ossifying myositis was diagnosed in a 2-year-old female cat. Clinical signs consisted of cervical pruritus, a stiff gait involving the forelimbs, and decreased range of motion of the scapulohumeral joints. The signs progressed over a 2-month period to involve the hindlimbs and coxofemoral joints. The primary cause of this disease is unknown and treatment is palliative. Treatment with diphosphonate disodium etidronate was unsuccessful in controlling the clinical signs in this case.

Fibrodysplasia ossificans in three cats.

A disseminated disorder of epimysial connective tissue characterized by hyperplasia and ossification causing atrophy and displacement of skeletal muscles, entrapment of vessels and nerves, and progressive immobility is described in three domestic cats. The condition has some features in common with fibrodysplasia ossificans progressiva in man.