Heterotopic Ossification Bone Formation in the Frontal Bones of an African Grey Parrot (Psittacus erithacus).

A 5-year-old, male African grey parrot (Psittacus erithacus) was presented with multiple, slow-growing, firm, bilateral masses around the dorsal orbital rims. Computer tomographic imaging revealed mild, incomplete bridging bone formation on the rostrodorsal aspects of the head. A moderate amount of smooth bone formation was identified at the rostrodorsal aspect to the left orbit, with minimal associated soft tissue swelling. Surgical biopsies were collected from the masses and histopathological analysis of the most rostral right mass showed well-differentiated bone, surrounded by dense fibrous connective tissue. Scattered, well-differentiated osteocytes were present within the bone. No evidence of neoplastic changes or infectious agents were identified. The histopathological changes were consistent with metaplastic bone formation. History obtained from the owner revealed recent head trauma, which likely induced the cranial heterotopic ossification in the African grey parrot.

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.

Computed tomography identified mineralisation of the longitudinal odontoid ligament of the horse is associated with age and sex but not with the clinical sign of head shaking.

Mineralisation of the longitudinal odontoid ligament has recently been identified in three horses undergoing computed tomographic (CT) examination, but published studies describing the clinical relevance of this finding are currently lacking. The objective of this retrospective, analytical, cross-sectional study was to investigate the relationship of this image finding to primary presenting complaint, age, breed, use and sex of the patient, and determine any association to the clinical signs of head shaking, neck pain or restricted range of neck motion. Computed tomographic images of 96 horses undergoing examination of the head and cranial cervical spine, for a variety of clinical reasons, were assessed for the presence of mineralisation within the longitudinal odontoid ligament. Clinical records were reviewed; presenting problem, signalment, clinical signs and final diagnoses were recorded and potential associations of presenting primary problem, signalment and individual clinical signs with mineralisation in the longitudinal odontoid ligament investigated, using univariable and multivariable ordinal logistic regression analysis. Final multivariable analysis confirmed significant associations of increasing severity of mineralisation with increasing age (P = .002) and being female (P = .038). There was no association of mineralisation of the longitudinal odontoid ligament with the syndrome of idiopathic head shaking or other clinical signs investigated in this sample of horses. Authors therefore recommend that the clinical significance of mineralisation of the longitudinal odontoid ligament be interpreted cautiously for equine CT studies.

Bilateral osteoma cutis in a Peach-Faced Lovebird (Agapornis roseicollis).

An osteoma is an infrequent tumor documented in avian species. An adult female Peach-Faced Lovebird (Agapornis roseicollis) with a history of previous trauma was examined due to the presence of bilateral hard and yellowish-white masses in the radio-cubital humerus junction. Histopathological dermal examination revealed a non-neoplastic process of mesenchymal origin, characterized by the formation of well-differentiated trabecular bone, multiple areas of medullary bone and loose connective tissue and coagulation of the necrosis foci. Based on the histological findings and the medical history, the masses were diagnosed as bilateral secondary osteoma cutis. To our knowledge, this is the first report of this pathology with an acute course in this exotic pet bird. The previous trauma could be the initiating cause.

Identification of the Identical Human Mutation in ACVR1 in 2 Cats With Fibrodysplasia Ossificans Progressiva.

Two domestic shorthair cats, 1 intact female and 1 intact male, presented with progressive limb lameness and digital deformities at 4 and 6 months of age. Stiffness and swelling of the distal thoracic and pelvic limb joints progressed to involve hip and shoulder joints, resulting in reduced mobility. Radiographs in both cats and computed tomography of the male cat revealed ankylosing, polyarticular deposits of extracortical heterotopic bone spanning multiple axial and appendicular joints, extending into adjacent musculotendinous tissues. All findings supported fibrodysplasia ossificans progressiva (FOP), a disorder characterized by toe malformations and progressive heterotopic ossification in humans. In both cats, molecular analyses revealed the same heterozygous mutation in the activin A receptor type I (ACVR1) gene that occurs in humans with FOP. Several reports of heterotopic ossification in cats exist, but this is the first one to identify clinical FOP in 2 cats with the identical mutation that occurs in >95% of humans with FOP.

Primary Osteoma Cutis in the Interscapular Region of a Dog.

A 9-year-old neutered male Shih Tzu was presented with three contiguous firm nodules in the subcutaneous tissue of the interscapular region. Histopathological examination revealed that the nodules consisted of mature lamellar bone with a Haversian system, with no apparent lesion around the bone. Clinical examination revealed that the dog had no underlying disease and no history of trauma at the lesion site. Based on these findings and on the medical history, a diagnosis of primary osteoma cutis was made. Osteoma cutis is rare in both human and veterinary medicine, and most dogs reported to have secondary osteoma cutis. To our knowledge, this case is only the second report of primary osteoma cutis in a dog.

Diagnosis and treatment of infraspinatus tendon-bursa ossification in a Eurasian Dog.

A 4-year-old male Eurasian Dog presented at our veterinary clinic with a history of perpetual forelimb lameness in both thoracic limbs. In the clinical exploration, direct pressure over the infraspinatus tendon of insertion caused pain in both thoracic forelimbs and a firm band-like structure was palpable. No improvement was observed after treatment with rest, non-steroidal anti-inflammatory drugs and an intralesional injection of a long-acting glucocorticoid. Radiographic examination, ultrasonographic exploration and computed tomography were performed, identifying ossified structures lateral to the proximal humerus and an irregular roughened periosteum at the insertion and tendon of the infraspinatus muscle on both sides. There were more distinct alterations on the right thoracic limb. The imaging results led to a diagnosis of an infraspinatus tendon-bursa ossification accompanied by a chronic tendinopathy/tendovaginitis, accentuated on the right side. The dog was subjected to physiotherapy and autologous conditioned plasma (ACP) was injected into the insertion of the infraspinatus muscle of both thoracic limbs. After 5 months of physiotherapy and two injections of ACP with an interval of one week in both forelimbs, the dog showed no signs of lameness. This case report describes the diagnosis and management of infraspinatus tendon-bursa ossification in a Eurasian Dog. To the authors' knowledge, this condition has previously not been described in this breed of dog.

Analysis of risk factors for elbow dysplasia in giant breed dogs.

OBJECTIVE: Identify radiographic risk factors for development of elbow dysplasia in giant breed dogs less than one year of age. METHODS: Twenty-five giant breed puppies (Bernese Mountain dogs, English Mastiff, and Newfoundland) were studied. Both elbows of each dog were radiographed monthly from two to six months of age, then every other month until radial and ulnar physeal closure, followed two months later by bilateral elbow computed tomography. Radiographic parameters measured included the presence or absence of a separate centre of ossification of the anconeal process (SCOAP), medial coronoid disease (MCD), ununited anconeal process, humeral osteochondrosis, elbow incongruity, as well as the length of the radius and ulna, radius-to-ulna ratio, and date of closure of the radial and ulnar physes. RESULTS: Fifteen dogs completed the study. Two Bernese Mountain dogs were diagnosed with MCD. Risk factors significantly associated with medial coronoid disease included dyssynchronous physeal closure and a decreased radius-to-ulna ratio, both detected between eight to 11 months of age. A separate centre of ossification of the anconeal process was present in 60% of the dogs, and was not a risk factor for development of elbow dysplasia. CLINICAL SIGNIFICANCE: Transient, dyssynchronous growth of the radius and ulna may be a risk factor for development of MCD in Bernese Mountain dogs. Dyssynchronous physeal closure or decreased radius-to-ulna ratio prior to radiographic closure of the distal ulnar and radial physes warrants further study in Bernese Mountain dogs and other breeds subject to MCD development.

Heterotopic Ossification Secondary to Gunshot and Fragment Wounds in a Golden Eagle ( Aquila chrysaetos ).

Heterotopic ossification is the process of pathologic bone formation in soft tissue structures that usually do not form bone. An immature golden eagle ( Aquila chrysaetos ) was examined 2 months after a gunshot wound in the right wing. A solid oval mass with a gun pellet at its core was found attached to the ulna by a bony pedicle and was surgically excised. Heterotopic ossification secondary to gunshot and fragment wounds in the right ulna was diagnosed based on clinical, radiographic, and histopathologic findings. This report is the first to describe heterotopic ossification occurring around a gun pellet in a bird.

Bilateral laryngeal paralysis in a dog secondary to laryngeal osseous metaplasia.

A 7-year-old spayed female Lurcher was evaluated for a chronic history of increased upper respiratory noise. Advanced imaging including digital radiography and pre- and post-contrast computed tomography (CT) scan confirmed the presence of an ill-defined soft tissue mineralized mass of the ventral larynx. Histopathology demonstrated pleocellular myositis and fasciitis with osseous metaplasia.

Paralysie laryngée bilatérale chez un chien secondaire à la métaplasie osseuse. Une chienne Lurcher stérilisée âgée de 7 ans a été évaluée pour une anamnèse chronique de bruit des voies respiratoires supérieures. Une imagerie avancée, dont une radiographie numérique et une image par tomodensitométrie avant et après contraste a confirmé la présence d'une masse minéralisée floue de tissus mous dans le larynx ventral. Unexamen histopathologique a démontré une myosite pléocellulaire et une fasciite avec une métaplasie osseuse.(Traduit par Isabelle Vallières).

PHAEOHYPHOMYCOSIS ASSOCIATED WITH OSSIFICATION OF THE SKULL AND CERVICAL VERTEBRAE IN A SWELL SHARK (CEPHALOSCYLLIUM VENTRIOSUM).

A female, captive bred, juvenile swell shark ( Cephaloscyllium ventriosum ) was observed swimming in tight circles and rolling. Radiographs and computed tomography of this individual revealed extensive cartilage mineralization of the skull and cranial cervical vertebrae compared with diagnostic images of clinically healthy conspecifics. Gross necropsy and histopathologic examination revealed ossification and fibrosis of the cartilaginous matrix of the skull and cervical vertebrae with deep invasion by a pigmented hyphal fungus. There was no growth on fungal culture, but fungal polymerase chain reaction identified a DNA sequence compatible with Exophiala sp. (99%). Radiographs and computed tomography were helpful to determine a prognosis and course of action for this individual. This case emphasizes the need to include fungal infections as a differential diagnosis when evaluating elasmobranchs with abnormal swimming behaviors and mineralization of the skeletal structures.

Primary isolated osteoma cutis causing eyelid deformation and strabismus in a dog.

Osteoma cutis describes bone formation in skin and is well documented in the medical literature, but veterinary reports are few. We report a single case of a juvenile samoyed that was referred for assessment of a superior eyelid anomaly. Exploratory surgery and histopathology revealed the presence of mature, lamellar bone within the superior eyelid. The histologic appearance was consistent with primary osteoma cutis. The presence of the ossification within the deep dermis of the eyelid was associated with an abnormal conformation causing trichiasis, keratitis and dorsal strabismus. Identification of the osseous lesion during surgery and its removal was curative with no recurrence of disease during the 32 month follow-up period.

Radiographic characterization of ossification of the ungular cartilages in horses: 271 cases (2005-2012).

OBJECTIVE: To describe in detail the radiographic appearance of ossified ungular cartilages in horses and to evaluate the usefulness of a flexed dorsolateral-palmaromedial oblique (flexed oblique) radiographic view in evaluating the ungular cartilages. DESIGN: Retrospective case series. Sample-Radiographs of 1,255 front feet of horses. PROCEDURES: Ossification of the ungular cartilages was graded during evaluation of radiographs on a scale from 0 to 5; feet with cartilages with an ossification grade ≥ 2 were included (386 feet [271 horses]). The shape (straight, curved outward or inward, and dorsopalmar extension of ossification) was determined. The view on which abnormalities were best identified was documented. Abnormalities of the compact bone, radiopacity, trabecular architecture, compactospongious demarcation, and presence of radiolucent lines were recorded; grouped as modeling, adaptive changes, or both; compared with ossification grade, separate centers of ossification, mediolateral symmetry of ossification, shape, cartilage (medial or lateral), and foot (left or right); and tested for significant associations. RESULTS: Fractures (n = 35) were most common in feet with cartilages with an ossification grade of 4 (18) or 5 (17) and were best identified in flexed oblique images, compared with more commonly recommended images. Multivariable logistic regression showed a significant positive association of ossification grade with modeling or adaptive changes; feet with cartilages with an ossification grade of 4 (OR, 11.59; 95% CI, 6.52 to 20.60) or 5 (OR, 72.90; 95% CI, 25.32 to 209.90) were more likely than those with an ossification grade of 2 or 3 to have modeling or adaptive changes. Abnormally shaped cartilages were more likely to have modeling or adaptive changes, compared with normally shaped cartilages (OR, 4.90; 95% CI, 1.94 to 12.42). CONCLUSIONS AND CLINICAL RELEVANCE: Extensive ossification and the presence of inward or outward curvature as well as palmar curvature or a bulbous shape were significant risk factors for modelling and adaptive changes. Flexed oblique images provided clinically useful information, including detection of abnormal shape and fractures, that may not be evident on other currently recommended images. Such images are recommended for complete radiographic appraisal of ossified ungular cartilages of the foot in horses.

Radiographic and computed tomographic assessment of the development of the antebrachia and elbow joints in Labrador Retrievers with and without medial coronoid disease.

OBJECTIVES: To compare the development, monitored by radiography and computed tomography, of the antebrachia and elbow joints in seven Labrador Retrievers with healthy elbow joints and in seven Labrador Retrievers that developed medial coronoid disease (MCD), in order to determine whether disturbances in the development of the antebrachia and elbow joints, between the age of six and 17 weeks may lead to medial coronoid disease. METHODS: A prospective study of 14 Labrador Retrievers in their active growth stage was performed. The development of the antebrachia and elbow joints was assessed between six and 17 weeks of age using radiography and computed tomography determining the development of secondary ossification centres, radioulnar length ratio, radial angulation, and inter-relationship between the humerus, ulna and radius. RESULTS: For the parameters of ossification of secondary ossification centres, radioulnar length ratio, radial angulation, and joint congruence evaluation, there was no significant difference in the development of the antebrachia and elbow joints of seven Labrador Retrievers positive and seven Labrador Retrievers negative for MCD at the age of six to 17 weeks. CLINICAL SIGNIFICANCE: These findings demonstrate that the development of MCD in the Labrador Retrievers in our study was not related to any disturbance in the development of the antebrachia and elbow joints during the rapid growth phase.

Lymphangiosarcoma with bone formation of the auricle in a dog.

A 12-year-old mixed-breed neutered female dog was referred with cutaneous tumors at the left auricle. Histologically, the cutaneous tumor located in the dermis comprised numerous clefts and cavernous channels lined by neoplastic endothelial cells with no erythrocytes. Bone tissue without direct contact with neoplastic cells was seen in the well-developed stromal connective tissue. The neoplastic endothelial cells exhibited mild to moderate atypia. Immunohistochemically, neoplastic cells were positive for vimentin and negative for cytokeratin and factor VIII-related antigen. Basement membrane around the neoplastic lumens was positive for laminin in a linear or granular pattern. Ultrastructural examination revealed discontinuous basement membrane beneath the tumor cells. Histopathological features of this case were consistent with lymphangiosarcoma, and stromal ossification was characteristic.

Ossification of ungular cartilages in front feet of cold-blooded trotters--a clinical radiographic evaluation of development over time.

BACKGROUND: It has not yet been shown that ossification of ungular cartilages (OUC) is a pathological condition. Beside heredity, factors such as sex, age, repeated concussion, local trauma, hoof and body size have been suggested as contributing factors for OUC development. By comparing radiographs of front hooves from cold-blooded trotters with different age we wanted to evaluate when development of OUC in cold-blooded trotters occurs and if and when it stabilizes in relation to age and workload. Diagnosis and grading of OUC were based on radiological field examinations of 649 Swedish and Norwegian cold-blooded trotters' front hooves. A hundred and forty-seven of the horses were re-examined 3-13 years (mean age 9, median 8 years) after the first occasion. All radiographs were evaluated blind, using two different grading systems for OUC. Work load, in form of number of races completed, and body size score were collected from official data. Four statistical ordinal regression models were used, compared and evaluated. RESULTS: We identified a breakpoint at 2.8 ± 0.38 years of age when ossification ends and proposed a simpler grading system with more consistent results. There was no significant correlation between body size and grade of OUC. Comparison of different statistical methods for evaluation of ordinal data revealed a piecewise linear regression model as most suitable. CONCLUSIONS: Individuals with OUC developed this condition during the stage of life when their hooves develop in size. Results from this study can assist equine practitioners when examining and for understanding this condition in their clinical work and is also beneficial for the Scandinavian equine industry when devising breeding programs.