Intracranial invasion of a mast cell tumour in a dog: A case report and review of the literature.

An 11-year-old, female-neutered beagle was presented with a growing soft tissue mass arising within the deep tissues of the left cranial cervical region. At presentation, facial asymmetry was evident along with palpable lymphadenomegaly. Magnetic resonance imaging demonstrated a locally invasive cervical mass with intracranial invasion through focal osteolysis of the occipital bone. After antihistamine administration, cytology confirmed mast cell tumour (MCT) with metastasis to local lymph nodes and liver. The owner chose to pursue lomustine and prednisolone, which were dispensed, but, before home administration, prolonged seizures/status epilepticus occurred prompting euthanasia. Postmortem examination confirmed a high-grade MCT associated with, and infiltrating through, muscle, calvarium, dura mata, leptomeninges and the underlying brain. We present the clinical, imaging, and pathological findings of an unprecedented case of extracranial MCT tumour causing osteolysis of an imperforate flat bone (occipital bone) and intracranial invasion.

Stabilisation of femoral capital physeal fractures using transcervical pinning in cats: 19 cases (2014-2022).

OBJECTIVES: To report the short-term clinical and radiographic outcomes in cats with femoral capital physeal fractures stabilised with transcervical pinning. MATERIALS AND METHODS: Medical records of cats diagnosed with femoral capital physeal fractures and treated with transcervical pinning were reviewed. The collected data included signalment, weight, time from lameness to surgery, reported trauma, affected side, concomitant orthopaedic injuries, radiographs, osteoarthritis, femoral neck osteolysis, proximal femoral epiphysis to femoral neck ratio, fracture reduction, implants, complications and clinical evaluation results. An owner questionnaire was used for long-term follow-up. RESULTS: Nineteen cats with a total of 21 fractures met the inclusion criteria. Fifteen of the 19 cats showed no signs of lameness at the 1-month follow-up. Major and catastrophic complications occurred in 9.5% and 23.8% of the fractures, respectively. All catastrophic complications occurred in fractures with a high preoperative osteolysis grade (2 or 3). CLINICAL SIGNIFICANCE: In our study, transcervical pinning was found to be a reliable fixation method for the treatment of femoral capital physeal fractures in cats with minimal preoperative femoral neck osteolysis. High rates of implant failure with loss of fracture reduction were observed in cats with high-grade preoperative osteolysis.

Metastasizing squamous cell carcinoma in a 50-year-old Eastern Hermann's tortoise (Testudo hermannii boettgeri).

A 50-year-old female Hermann's tortoise (Testudo hermannii boettgeri) was presented with anorexia and lethargy. Clinical examination revealed multiple, visually inconspicuous but indentable areas in the shell corresponding to osteolysis radiographically. Soft tissue nodules and osteolytic lesions were also noted in the limbs. Laboratory results revealed elevated aspartate aminotransferase activity and uric acid concentrations, hypoglycemia, and hyperphosphatemia. Klebsiella oxytoca was isolated from a biopsied scutal area, and the biopsy suggested neoplasia. After a short period of clinical improvement, the animal's condition deteriorated, and it died. Post mortem computed tomography revealed polyostotic lytic lesions of multiple bones and the shell with associated soft tissue nodules protruding into the coelom, and nodular lung lesions. Necropsy, histopathology, and immunohistochemistry secured a diagnosis of a poorly differentiated, pan-cytokeratin-positive squamous cell carcinoma with widespread soft tissue and bone metastases, osteolysis and desmoplasia.

Computed tomographic, magnetic resonance imaging, and ultrasonographic characteristics of retrobulbar meningiomas in 15 dogs.

Meningioma is the most common tumor of the cranium in dogs and an important differential diagnosis for a potentially treatable disease that can be found in the periorbital tissues. The objective of this retrospective, case series study was to describe the CT, MRI, and US characteristics of confirmed retrobulbar meningiomas in a group of dogs. Medical records from multiple institutions were searched for canine patients with CT, MRI, and/or US imaging of a cytologically or histologically confirmed retrobulbar meningioma. Fifteen dogs met the inclusion criteria. Retrobulbar meningiomas typically appeared as a relatively well-defined conical to ovoid mass within the retrobulbar space, most often along the optic nerve and expanding the extraocular muscle cone. On CT, masses were predominantly soft tissue attenuating and variably heterogeneously contrast enhancing. While MRI features were variable, moderate to marked contrast enhancement was seen in all cases. Many of the tumors had evidence of partial mineralization, best appreciated on CT in nine patients, but also suspected based on susceptibility artifacts in three MRI cases, one of which was confirmed on CT. Regional osteolysis was a rare finding, noted in three cases, but was often accompanied by cranial cavity extension (2/3). Cranial cavity extension was also seen in the absence of regional osteolysis, identified in a total of six patients. On US, masses were echogenic and compressed the globe. The findings were consistent with previous gross and histologic descriptions and supported prioritizing retrobulbar meningioma as a differential diagnosis for dogs with the described imaging characteristics.

Treatment of Septic Tenosynovitis and Osteoarthritis in an American White Pekin (Anas platyrhynchos domesticus) with Repeated Intravenous Regional Limb Perfusion and Antibiotic-Impregnated Calcium Sulfate Beads.

A 2-year-old female American white pekin (Anas platyrhynchos domesticus) was assessed for a 2-month history of chronic lameness and swelling involving the left leg. Radiographic images of the left leg showed soft tissue swelling of the digits and tarsometatarsus with osteolysis of the tarsometatarsal-phalangeal joint. A complete blood count revealed marked leukocytosis and hyperproteinemia. A Streptococcus species was isolated from a bacterial culture of fluid obtained from the left tarsometatarsal-phalangeal joint. Biweekly intravenous regional limb perfusions of the left leg with ampicillin-sulbactam and amikacin were performed on the patient. Despite initial improvement in left leg lameness and swelling, follow-up radiographic images showed progressive osteolysis of the tarsometatarsal-phalangeal joint and associated digits. Surgical placement of antibiotic-impregnated calcium sulfate beads into the left tarsometatarsal-phalangeal joint was next performed with concurrent, repeated intravenous regional limb perfusion using the same antibiotic. Following the placement of antibiotic-impregnated beads and continued intravenous regional limb perfusion, the duck had decreased lameness and swelling of the left leg. Repeated antibiotic treatment through intravenous regional limb perfusion and concurrent placement of antibiotic-impregnated calcium sulfate beads is a practical treatment option for complicated distal limb infections in avian species. This therapeutic protocol has great potential in treating aggressive distal leg infections in many avian species because regional limb perfusion alone may not penetrate the joint adequately to achieve complete resolution of infection.

Invasive spindle-cell rhabdomyosarcoma with osteolysis in a dog: case report and literature review.

Rhabdomyosarcoma (RMS), a malignant mesenchymal neoplasm derived from skeletal muscle, is relatively rare in both human and veterinary medicine. Here we report an unusual case of invasive spindle-cell RMS (SCRMS) with bone infiltration and pathologic fracture in a 3.5-y-old intact female Bulldog. Radiographically, a large, predominantly osteolytic mass in the tibia and fibula of the left hindlimb had features typical of a malignant primary bone tumor. Clinically, osteosarcoma was suspected, and the leg was amputated. Histologically, the mass was composed of loosely interwoven spindle-cell fascicles; tumor cells were fusiform with cigar-shaped nuclei and abundant eosinophilic cytoplasm. The neoplastic cells were strongly immunopositive for vimentin, muscle-specific actin, desmin, myogenin, and myoD1. Invasive SCRMS with osteolysis was diagnosed based on the histologic examination and immunohistochemical (IHC) stains. The dog was alive without any evidence of local recurrence or distant metastasis 18 mo post-surgery. RMS should be included in the differential diagnosis when osteolysis occurs; IHC staining confirmation is of great value for definitive diagnosis and treatment planning.

Computed tomography features of discospondylitis in dogs.

BACKGROUND: Computed tomography (CT) findings of dogs with discospondylitis have not been widely described despite increased availability of this imaging modality. OBJECTIVES: Describe the CT features of discospondylitis in a population of clinically affected dogs with discospondylitis diagnosed by magnetic resonance imaging (MRI). ANIMALS: Forty-one dogs (63 affected discs) with MRI-identified discospondylitis presented to a single referral hospital between 2012 and 2022. METHODS: Retrospective, single center, descriptive case series with analysis of MRI-identified discospondylitis sites and concomitant CT imaging. Computed tomographic features of MRI-affected sites including intervertebral disc space (IVDS), endplates, vertebral body, epidural space and paraspinal tissues were described. RESULTS: The most frequently found changes were: (1) endplate involvement (87.3%) most frequently bilateral (94.5%), with erosion (61.9%) and multifocal osteolysis (67.3%); (2) periosteal proliferation adjacent to the IVDS (73%) and spondylosis (66.7%); and (3) vertebral body involvement (66.7%) involving one-third of the vertebra (85.7%) with multifocal osteolysis (73.5%). Other less prevalent features included an abnormal IVDS (narrowed or collapsed), sclerosis of the adjacent vertebral body or endplates, presence of disseminated idiopathic skeletal hyperostosis or vacuum artifact. CONCLUSIONS AND CLINICAL IMPORTANCE: We determined that bilateral endplate erosion and periosteal proliferation were very common in dogs with discospondylitis. Careful evaluation of CT in all 3 planes (dorsal, sagittal, transverse) is necessary to identify an affected IVDS. These described CT features can aid in the diagnosis of discospondylitis in dogs but equivocal cases might still require MRI.

Short-Term Clinical and Radiographic Outcome after Stabilization of Femoral Capital Physeal Fractures with Cortical Positional Screws in 39 Cats.

OBJECTIVE: The aim of this study was to report the short-term clinical and radiographic outcome for the treatment of femoral capital physeal fractures with cortical positional screws in cats. STUDY DESIGN: Medical records and radiographs of cats with femoral capital physeal fractures stabilized with cortical positional screws were retrospectively reviewed. Signalment, bodyweight, femoral head affected, fracture classification, fracture reduction, implants, concurrent orthopaedic injuries, osteoarthritis, femoral neck osteolysis, complications and 6-week follow-up clinical results were recorded. A short- to long-term follow-up was performed by telephone questionnaire with the owners. RESULTS: Forty-six fractures in 39 cats met the inclusion criteria. In 45/46 fractures, radiographic signs of bone healing were present and 35/39 cats were assessed as walking normally by a veterinarian at 6-week follow-up. There was a significant increase in radiographic signs of osteoarthritis (p=0.037) and femoral neck osteolysis (p=0.001) on 6-week follow-up radiographs. Pre- and postoperative osteoarthritis and femoral neck osteolysis were not associated with clinical outcome. The mean follow-up period for the telephone questionnaire was 48 months (range, 5-147 months). Seven out of 25 owners reported a gait abnormality in the short- to long-term. CONCLUSION: Femoral capital physeal fractures in cats can be treated successfully with the use of cortical positional screws. This technique may be considered as an alternative to other primary fixation techniques and salvage procedures for the treatment of femoral capital physeal injuries in cats. This technique seemed successful in cats with a low-grade preoperative femoral neck osteolysis.

Combining radiation therapy with zoledronate for the treatment of osteo-invasive feline oral squamous cell carcinoma.

Feline oral squamous cell carcinoma (FOSCC) is the most common oral tumour diagnosed in pet cats and carries a poor prognosis with <10% one-year survival despite multi-modal therapies. Tumours of the mandible or maxilla are frequently osteo-invasive and pain can result from osteolysis. Zoledronate is a bisphosphonate that inhibits osteoclasts and reduces bone resorption. Radiation therapy (RT) is used to treat FOSCC due to anti-cancer activity and ability to improve quality of life. We hypothesized RT can be safely combined with zoledronate, and that this combinatory therapy would be efficacious, well tolerated, and result in decreased bone resorption in cats with FOSCC. SCCF1 cell line was treated with zoledronate before, concurrently, or after RT, and clonogenic assays were performed to determine if an optimal dosing schedule would be identified. Nine cats with osteoinvasive FOSCC were recruited for treatment with 4 weekly doses of 8 Gy RT combined with zoledronate administered at the first and fourth treatments. Serial CT scans were performed to assess tumour response. Safety and tolerability were monitored with hematologic and biochemical parameters, and acute radiation effects were characterized. Serum c-telopeptide (CTx) and relative bone mineral density (rBMD) by dual -energy X-ray absorptiometry (DEXA) quantified bone resorption. In vitro studies showed no clear benefit to timing of zoledronate with RT, therefore all zoledronate was administered concurrently with RT in FOSCC patients. Based on tumour volume, 4/9 (44.4%) cats achieved partial remission, 4/9 (44.4%) stable disease and 1/9 (11.1%) had progressive disease. The combinatory therapy was well-tolerated based on biochemical measurements, and all patients experienced decreased serum CTx. Combining RT with zoledronate in tumour-bearing cats is safe, well-tolerated, results in a partial remission rate of up to 44%, and decreases serum CTx, a marker of bone resorption.

Cranial and vertebral osteosarcoma commonly has T2 signal heterogeneity, contrast enhancement, and osteolysis on MRI: A case series of 35 dogs.

Magnetic resonance imaging (MRI) is commonly used to evaluate the central nervous system (CNS) in dogs; however, published studies describing the MRI appearance of cranial and vertebral osteosarcoma are scarce. In this multicenter, retrospective, case series study, MRI studies of 35 dogs with cranial or vertebral osteosarcoma were prospectively scored by consensus of two veterinary radiologists. Recorded characteristics were location, signal intensity (compared to gray matter), homogeneity, contrast enhancement, margin delineation, local invasion, osteolysis, osteosclerosis, zone of transition, periosteal proliferation, pathological fracture, meningeal/CNS involvement, and presence of metastatic disease. Locations included the parietal bone (n = 1), occipital bone (n = 2), or cervical (n = 5), thoracic (n = 17), lumbar (n = 7), or sacral vertebrae (n = 3). Common features included signal heterogeneity in T2-weighted (T2W) images (n = 35), contrast enhancement (in all 34 dogs with postcontrast MRI), osteolysis (n = 34), compression of the CNS or cauda equina (n = 33), an associated soft tissue mass (n = 33), a long zone of transition (n = 30), osteosclerosis (n = 28), signal isointensity to normal-appearing gray matter in T1-weighted images (T1W, n = 26), and T2W hyperintensity of adjacent brain or spinal cord (n = 23). Other findings included periosteal proliferation (n = 18), meningeal contrast enhancement (n = 17), T1W and T2W hypointense foci in the soft tissue mass (n = 14), invasion into adjacent bones (n = 10), pathological vertebral fractures (n = 7), regional lymphadenopathy (n = 6), skip metastases (n = 2), lung nodule (n = 1), diaphragmatic nodule (n = 1), and brain invasion (n = 1). Contrast enhancement was typically strong and heterogeneous. Magnetic resonance imaging features of cranial and vertebral osteosarcoma were analogous to those previously reported for other imaging modalities. Osteosarcoma should be a differential diagnosis for compressive, contrast-enhancing, osteolytic lesions of the cranium or vertebrae.

Radiographic characteristics of canine subungual keratoacanthoma.

Subungual keratoacanthoma (SKA) is a rare benign nail bed tumor in dogs, and its radiographic characteristics have not been reported based on the authors' review of the literature. The purpose of this multicenter, retrospective, observational, descriptive study was to describe the radiographic features of SKA in dogs. Twelve dogs for a total of 12 digits with histologically confirmed SKA met the inclusion criteria. The radiographs of the manus or pes were reviewed by two veterinary radiologists and one veterinarian. The radiology reports were interpreted based on a consensus. In six dogs, there was lysis of both the middle phalanx (P2) and the distal phalanx (P3), whereas in the other six dogs, there was only lysis of P3. In all dogs with osteolysis of P2, the lysis involved the distal articular surface. Osteolysis of P3 was more severe in the ungual process than in the ungual crest in all dogs. The margins of the lytic regions of P2 and P3 were well defined and smoothly marginated in most dogs. Expansile changes in the P3 crest were observed in 83.3% (10/12 dogs), and the nail of the affected digit was enlarged and deformed in 91.6% (11/12 dogs). In summary, the radiographic features of canine SKA include severe pressure resorption of the P3 ungual process, expansile change of the P3 ungual crest, and nail enlargement and deformation. With these radiographic features, SKA should be considered as a differential diagnosis.

Clinical, advanced imaging data and outcome of inflammatory and neoplastic orbital disease in 81 dogs and 16 cats in Australia (2010-2019).

OBJECTIVE: To characterize the clinical presentation, advanced imaging features, and outcome of orbital disease in a referral population of dogs and cats that underwent computed tomography (CT) or magnetic resonance imaging (MRI). ANIMALS STUDIED: Client-owned animals. PROCEDURES: Animals referred for orbital disease undergoing ophthalmic examination and either head MRI or CT were included. Demographic and imaging features were compared between animals diagnosed with inflammatory disease and neoplastic disease using Mann-Whitney U and Fischer's exact tests. RESULTS: Ninety-seven animals (81 dogs and 16 cats) were included. Eighty-four and 13 patients underwent CT and MRI scanning, respectively. Inflammatory orbital disease was more frequently detected than neoplasia in dogs (59% vs. 41%) and cats (62% vs. 39%). Orbital cellulitis was the most common diagnosis in dogs (36/81, 44.4%) and cats (8/16, 80%). A foreign body was suspected in 36.1% of dogs with orbital cellulitis but only 3 were retrieved during orbitotomy. Multi-drug resistant bacteria were identified in 3 samples and influenced treatment plans. The most common neoplasms were sarcoma (10/30) and carcinoma (7/30) in dogs and lymphoma in cats (3/6). Imaging findings of osteolysis (p = 0.0002) and intracranial extension (p = 0.0001) were significantly associated with neoplasia in dogs. In contrast, osteolysis extension was present in cats with both inflammatory (7/10) and neoplastic (6/6) orbital disease. CONCLUSIONS: Inflammatory disease, particularly orbital cellulitis, was more common than neoplasia in dogs and cats with orbital disease in our population. We recommend including bacterial culture and susceptibility as part of the diagnostic work up when orbital cellulitis is suspected.

Periarticular plasma cell tumors in cats.

This report describes periarticular plasma cell tumors with abundant amyloid in 11 cats. The tarsus was the most commonly affected joint (10/11), and the masses were often circumferential around the tarsal joint, involving the dermis and subcutis. The 2 cases in which synovium was examined had neoplastic cells expanding the synovium. Three of the 5 cases staged radiographically had bony lysis of the affected joint. Cutaneous biopsy specimens often consisted of more amyloid than plasma cells, making the diagnosis difficult on small samples. Follow-up information was available in 7 cases; in those cases, the median survival was 194 days (range 53-671 days). Four cases had confirmed metastases, most often to regional lymph nodes, liver, and spleen. Although canine cutaneous plasma cell tumors are typically benign, those with abundant amyloid surrounding the joints of cats may involve deeper tissues and have a more aggressive behavior. These tumors can be difficult to diagnose due to low cellularity and abundant amyloid.

Invasive Tendon Sheath Fibrosarcoma Causing Radial Osteolysis in a Golden Retriever.

This case report details a previously undescribed malignancy of the tendon sheath in a golden retriever. This dog originally presented with lameness of the left forelimb, at which point radiographs revealed a monostotic, lytic lesion of the distal radius with overlying soft-tissue swelling. A fine-needle aspirate was performed, and cytology was compatible with a sarcoma, with the primary differential being an osteosarcoma. After amputation, the leg was submitted for histopathology, which revealed inconsistencies with a typical osteosarcoma lesion, including lack of osteoid deposition. Second opinion histopathology showed a fibrosarcoma that appeared to have originated in the tendon sheath of an extensor tendon and then secondarily invaded the radius. At the time of publication, ∼17 mo after amputation, the dog continues to do well without any evidence of recurrent or metastatic disease.

Computed tomography of tympanic bullae in pre-weaned dairy calves diagnosed with clinical respiratory disease.

Clinical disease from otitis media in calves is a significant problem in the dairy industry and evaluation of disease severity, chronicity, and imaging remains a challenge. Our objectives were to compare imaging findings in calves with an early diagnosis of respiratory disease to calves with treatment failure. This was a prospective study of 30 Jersey heifer calves, 26-95 days of age, with elevated clinical respiratory scores. Ten clinically healthy calves served as controls for clinical scoring. Three groups of calves were selected based on elevated scores using the McGuirk respiratory scoring system and treatment history. Group A included new cases, group B included primary treatment failures, and group C included multiple treatment failures. Calves underwent a skull CT, four view radiography, post-mortem photography of the tympanic bulla and bacteriological diagnostics. Imaging and post-mortem results were evaluated using normalized scoring schemes. Computed tomography imaging of the tympanic bulla differentiated calves early in the course of disease (group A) from calves that had not responded to treatment (groups B and C). Radiographs differentiated only group C from groups A and B. Use of a 35 degree angle dorsal-right or dorsal-left ventral oblique projection for radiography allowed effective evaluation of the tympanic bulla. Clinical respiratory scores were similar among all three groups. Computed tomography imaging can differentiate early from advanced otitis media. Radiographs, which can be performed in the field, also have utility to identify advanced otitis media to aid management decisions.

Metastatic Osteolytic Angioleiomyosarcoma Induced by a Foreign Body in a Kangaroo (Macropus giganteus).

An adult female Eastern Grey kangaroo (Macropus giganteus) was examined for lameness due to a mass located at the right tibiotarsal joint. Radiographs revealed a metal arrowhead-shaped foreign body within the mass alongside a pathologic fracture. Grossly, at necropsy, there was a multilobulated and haemorrhagic mass with intralesional metal fragments, associated osteolysis of the tibiotarsus and pulmonary metastatic nodules. Histologically the neoplasm was composed of plump elongated and fusiform cells that often formed concentrically around small vessels. The pulmonary nodules were composed of similar neoplastic cells, necrosis and haemorrhage. Neoplastic cells were positive immunohistochemically for vimentin and smooth muscle actin. The histological features, immunohistochemical profiles and behaviour of this tumour support a diagnosis of a primary angioleiomyosarcoma with lung metastasis associated with a metal foreign body.

Magnetic resonance imaging and computed tomographic characteristics of a glioma causing calvarial erosion in a dog.

An 8-year-old female Boxer was examined for acute onset of seizures. On magnetic resonance imaging (MRI), an intra-axial mass with imaging features consistent with glioma was observed in the right cerebral hemisphere. A defect in the temporal bone adjacent to the mass was observed. Postmortem computed tomography (CT) confirmed temporal bone osteolysis and necropsy demonstrated a glioblastoma with associated calvarial erosion. Although occasionally described in human medicine, to our knowledge, this is the first description of a brain glioma causing calvarial erosion in a dog. Glioma should be included as a differential diagnosis for intracranial lesions that could cause bony changes in the skull.

Metallosis in a Dog as a Long-Term Complication Following Total Hip Arthroplasty.

Metallosis is the accumulation of metallic debris in soft tissues resulting from wear following total joint replacement. A dog was evaluated for lameness 4 years after total hip arthroplasty using a titanium alloy and cobalt chromium total hip system. Radiographs revealed severe acetabular component wear, implant-bone interface deterioration, and peri-acetabular osteolysis. During surgical revision, black periarticular tissue surrounded the implants. Histologically, there was fibrosis and granulomatous inflammation with abundant, intra- and extracellular, black, granular material and smaller amounts of clear punctate to acicular material. Laser capture microdissection followed by x-ray fluorescence microscopy indicated the material contained large amounts of titanium with smaller amounts of vanadium, cobalt, and chromium, confirming the diagnosis of metallosis. The clear material was birefringent under cross-polarized light, stained positive with Oil-Red-O, and thus was consistent with polyethylene. Metallosis exhibits characteristic gross and histologic lesions and is a differential diagnosis for aseptic loosening of hip implants.