Adjuvant electrochemotherapy after debulking in canine bone osteosarcoma infiltration.

Osteosarcoma is a bone cancer considered rare to humans, but common in dogs. Dogs and humans share genetic homology and environmental risk factors. Improving the treatment of osteosarcoma in dogs could also be relevant to improve procedures in humans. Traditional treatments of osteosarcoma involve surgery and chemotherapy. Such treatments are commonly aggressive and not possible for many patients. Electrochemotherapy emerges as a minimally invasive, effective, and safe treatment alternative. Electrochemotherapy combines applications of high-intensity electric fields during short periods with anti-cancer drugs to improve its medicine cytotoxicity. Analyzing the electric field distribution, as well as electric current density, are essential to electrochemotherapy success. This paper brings the first case of a canine osteosarcoma treatment performed with bleomycin and electrochemotherapy. We performed in silico studies with finite element method software to observe the electric field distribution. In silico experiments help to verify possibilities and limitations of treating bone destruction and macro or micro tumor infiltrations around the primary tumor mass. Results show that both needle or plate electrodes are feasible to remove the tumor even with invasion into the bone. Plate electrodes perform well in treating micro infiltrations when associated with conductive gel and direct contact between electrode and bone (without soft tissues). Needle electrodes are effective in treating tumor infiltration on external cortical bone. Multiple applications are needed to cover all cranium layers with sufficient electric field intensity. Electrochemotherapy protocol with needle or plate electrodes does not present sufficient electric current density capable of affecting brain tissue, even in cases of bone destruction.

Schedule feasibility and workflow for additive manufacturing of titanium plates for ranioplasty in canine skull tumors.

BACKGROUND: Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty immediately following craniectomy. RESULTS: Computed tomography scans from patients with tumors of the skull were considered and 3 cases were selected. Images were imported into a DICOM image processing software and tumor margins were determined based on agreement between a board-certified veterinary radiologist and veterinary surgical oncologist. Virtual surgical planning was performed and a bone safety margin was selected. A defect was created to simulate the planned intraoperative defect. Stereolithography format files of the skulls were then imported into a plate design software. In collaboration with a medical solution centre, a custom titanium plate was designed with the input of an applications engineer and veterinary surgery oncologist. Plates were printed in titanium and post-processed at the solution centre. Total planning time was approximately 2 h with a manufacturing time of 2 weeks. CONCLUSIONS: Based on the findings of this study, with access to an advanced 3D metal printing medical solution centre that can provide advanced software and printing, patient-specific additive manufactured titanium implants can be planned, created, processed, shipped and sterilized for patient use within a 3-week turnaround.

The use of a 3D-printed prosthesis in a Great Hornbill (Buceros bicornis) with squamous cell carcinoma of the casque.

The advent of new technologies in medical imaging and 3D printing in recent years has made customization of surgical tools and implants more accessible, revolutionizing many surgical fields. In many human diseases, these implants have led to superior surgical outcomes and greatly improved patients' quality of life. Thus, it is of great interest to apply these technologies to the treatment of animal diseases. In this study, we report the use of computed tomography (CT) and 3D printing for the treatment of a Great Hornbill at Jurong Bird Park that was diagnosed with squamous cell carcinoma of the casque. A 3D printed prosthesis that perfectly fitted the subject was implanted to replace its resected casque. The subject exhibited natural eating behaviour with no post-operative complications. Using this case as an example, the positive outcomes suggest a great potential in applying these technologies to the treatment of other wildlife diseases.

Treatment of calvarial defects by resorbable and non-resorbable sonic activated polymer pins and mouldable titanium mesh in two dogs: a case report.

BACKGROUND: To date, calvarial defects in dogs have traditionally been addressed with different types of implants including bone allograft, polymethylmethacrylate and titanium mesh secured with conventional metallic fixation methods. This report describes the use of an absorbable and non absorbable novel polymer fixation method, Bonewelding® technology, in combination with titanium mesh for the repair of calvarial defects in two dogs. The clinical outcomes and comparative complication using resorbable and non-resorbable thermoplastic pins were compared. CASE PRESENTATION: This report of two cases documents the repair of a traumatic calvarial fracture in an adult male Greyhound and a cranioplasty following frontal bone tumor resection in an adult female Cavalier King Charles Spaniel with the use of a commercially available titanium mesh secured with an innovative thermoplastic polymer screw system (Bonewelding®). The treatment combination aimed to restore cranial structure, sinus integrity and cosmetic appearance. A mouldable titanium mesh was cut to fit the bone defect of the frontal bone and secured with either resorbable or non-resorbable polymer pins using Bonewelding® technology. Gentamycin-impregnated collagen sponge was used intraoperatively to assist with sealing of the frontal sinuses. Calvarial fracture and post-operative implant positioning were advised using computed tomography. A satisfactory restoration of skull integrity and cosmetic result was achieved, and long term clinical outcome was deemed clinically adequate with good patient quality of life. Postoperative complications including rostral mesh uplift with minor associated clinical signs were encountered when resorbable pins were used. No postoperative complications were experienced in non-resorbable pins at 7 months follow-up, by contrast mesh uplift was noted 3 weeks post-procedure in the case treated using absorbable pins. CONCLUSIONS: The report demonstrates the innovative use of sonic-activated polymer pins (Bonewelding® technology) alongside titanium mesh is a suitable alternative technique for skull defect repair in dogs. The use of Bonewelding® may offer advantages in reduction of surgical time. Further, ultrasonic pin application may be less invasive than alternative metallic fixation and potentially reduces bone trauma. Polymer systems may offer enhanced mesh-bone integration when compared to traditional metallic implants. The use of polymer pins demonstrates initial potential as a fixation method in cranioplasty. Initial findings in a single case comparison indicate a possible advantage in the use of non-absorbable over the absorbable systems to circumvent complications associated with variable polymer degradation, further long term studies with higher patient numbers are required before reliable conclusions can be made.

CALVARIAL OSTEOSARCOMA WITH CEREBRAL COMPRESSION IN A FREE-RANGING POWERFUL OWL (NINOX STRENUA).

A free-ranging powerful owl (Ninox strenua) presented in a dull state with extensive bruising of the skin overlying the skull, due to suspected trauma. Supportive care was provided, which resulted in the return to a normal state, although intermittent subtle neurologic abnormalities remained. One month from original presentation, intermittent episodes of head turning and a possible seizure were noted, but behavior and appetite were otherwise normal. The owl was referred to Taronga Wildlife Hospital for evaluation. On presentation, the owl exhibited severe neurologic abnormalities, prompting euthanasia. At necropsy the dorsum of the skull exhibited marked osseous proliferation, extending ventrally and compressing the cerebrum. The skull was radiographed and submitted for histopathology. A diagnosis of osteoblastic osteosarcoma was made. This is the first report of a calvarial osteosarcoma in a powerful owl.

Blindness associated with nasal/paranasal lymphoma in a stallion.

A 29-year-old stallion presented with bilateral blindness following the chronic purulent nasal drainage. The mass occupied the right caudal nasal cavity and right paranasal sinuses including maxillary, palatine and sphenoidal sinuses, and the right-side turbinal and paranasal septal bones, and cribriform plate of ethmoid bone were destructively replaced by the mass growth. The right optic nerve was invaded and involved by the mass, and the left optic nerve and optic chiasm were compressed by the mass which was extended and invaded the skull base. Histologically, the optic nerves and optic chiasm were degenerated, and the mass was diagnosed as lymphoma which was morphologically and immunohistochemically classified as a diffuse large B-cell lymphoma. Based on these findings, the cause of the blindness in the stallion was concluded to be due to the degeneration of the optic nerves and chiasm associated with lymphoma occurring in the nasal and paranasal cavities. To the best of our knowledge, this is the first report of the equine blindness with optic nerve degeneration accompanied by lymphoma.

Cranioplasty Using Titanium Mesh After Skull Tumor Resection in Five Dogs.

OBJECTIVE: To describe the clinical details, surgery, postoperative imaging, and short to mid-term outcome after cranioplasty with titanium mesh in dogs with large skull tumors. STUDY DESIGN: Case series. ANIMALS: Client-owned dogs with skull tumors (n=5). METHODS: All tumors were removed via craniectomy and a sheet of titanium mesh was contoured to reconstruct the calvarial defect and sutured to surrounding musculature. RESULTS: Four dogs had multilobular tumors of bone and 1 dog had a soft tissue sarcoma invading the cranial vault. Neurologic examination was unchanged or improved postoperative, a good cosmetic appearance was achieved, and no complications were noted at 2 weeks postoperative. Late postoperative computed tomography (CT) in 2 dogs and magnetic resonance (MR) imaging in 1 dog confirmed the presence of the titanium mesh without migration. There was no interference of the mesh with image interpretation and definitive radiation therapy was pursued in 1 dog without complication. Late follow-up reported 2 dogs euthanatized; at 44 weeks postoperative due to tumor re-growth; at 12 weeks postoperative for hemoabdomen, respectively. One dog drowned at 40 weeks postoperative, 1 dog was lost to follow-up, and 1 dog is alive at 83 weeks postoperative free of clinical signs. CONCLUSIONS: Titanium mesh is suitable for cranioplasty based on its strength, biocompatibility, and excellent handling characteristics. It does not interfere with acquisition or interpretation of CT or MR images, thereby allowing postoperative imaging for ongoing assessment.

IMAGING DIAGNOSIS: COMPUTED TOMOGRAPHIC FINDINGS IN A CASE OF ADENOSQUAMOUS CARCINOMA OF THE HEAD AND NECK IN A CAT.

A 15-year-old female spayed domestic long-haired cat was referred for trismus, hypersalivation, and bilateral ocular discharge. On examination, the cat showed pain on palpation of the left zygomatic arch, palpable crepitus of the frontal region, and limited retropulsion of both globes. A contrast-enhanced sinonasal computed tomographic study was performed, showing facial distortion and extensive osteolysis of the skull, extending beyond the confines of the sinonasal and paranasal cavities. Additionally, soft tissue and fluid accumulation were observed in the nasal cavities and paranasal sinuses. Postmortem biopsy samples acquired from the calvarium yielded a histologic diagnosis of sinonasal adenosquamous carcinoma, a rare and particularly aggressive neoplasm previously only reported in the esophagus of one cat.

Calvaria and orbital metastases of pulmonary adenosquamous carcinoma in a cat: a diagnostic challenge.

An 11-year-old cat with a 4-month history of lethargy, inappetence, dysphagia, partial mandibular paralysis and weight loss, was euthanized due to the rapid deterioration of his condition. Post-mortem radiographic examination revealed severe bone lysis of the left zygomatic arch, temporal and parietal bones. Magnetic resonance imaging of the head showed a large isointense mass of the left side of the skull associated with extensive lysis of the parietal and temporal bones and destruction of the adjacent tympanic bulla. Gross and histological examinations revealed a pulmonary adenosquamous carcinoma of the left lung, with metastases to the spleen, liver, mesenteric lymph nodes, mesentery, diaphragm, abdominal aorta, left orbit and calvaria. No limb or digit metastases were detected.

Outcome and prognostic factors for osteosarcoma of the maxilla, mandible, or calvarium in dogs: 183 cases (1986-2012).

OBJECTIVE: To describe the biological behavior, clinical outcome, and prognostic factors of osteosarcoma of the maxilla, mandible, or calvarium in dogs. DESIGN: Retrospective case series. ANIMALS: 183 client-owned dogs with osteosarcoma of the maxilla, mandible, or calvarium. PROCEDURES: Medical records for dogs treated for osteosarcoma of the maxilla, mandible, or calvarium from 1986 through 2012 were reviewed. Dogs with a histopathologic diagnosis of osteosarcoma and treated for a primary tumor arising from these bones of the head were included. RESULTS: Mean age was 9.3 years, and body weight was 31.8 kg (70.0 lb). Most dogs (124/183 [67.8%]) were purebred, and the most common primary tumor site was the maxilla (80 [43.7%]). Treatments included palliative medical treatment only (11/183 [6.0%]), coarsely fractionated radiation therapy (RT; 12 [6.6%]), fractionated or stereotactic RT (18 [9.8%]), surgery (135 [73.8%]), and both surgery and fractionated RT (7 [3.8%]). Eighty-three (45.4%) dogs received adjuvant chemotherapy. Local recurrence or progression occurred in 80 of 156 (51.3%) dogs, and 60 of 156 (38.5%) dogs developed distant metastases. Median survival time for all dogs was 239 days. Dogs that underwent surgery had a median survival time of 329 days. Histologically tumor-free surgical margins were associated with significantly decreased hazards of progression or recurrence (hazard ratio [HR], 0.4) and death (HR, 0.5). Dogs with osteosarcoma of the calvarium had a significantly greater hazard of local recurrence or progression (HR, 2.0). CONCLUSIONS AND CLINICAL RELEVANCE: In this study, tumor excision in dogs with histologically tumor-free margins resulted in better local control and longer survival time than did other treatment types.

Oral and maxillofacial osteosarcoma in dogs: a review.

Osteosarcoma in dogs is a heterogeneous disease entity with regard to its histologic, clinical and biologic behaviour. Differences in behaviour are associated with tumour location. Oral and maxillofacial osteosarcomas are typically reported as a component of the broader classifications of axial osteosarcoma or osteosarcoma of flat bones to differentiate them from appendicular osteosarcoma. Similar to human oral and maxillofacial osteosarcoma, in dogs, these also appear to have less aggressive behaviour than appendicular osteosarcoma. Ideally, local control is achieved with wide surgical resection that results in tumour-free margins. Failure of local control is the most common contributor to poor prognosis. Chemotherapy and radiation treatment are reported to have variable outcomes. The aim of this article is to review the literature on oral and maxillofacial osteosarcoma in dogs in comparison to appendicular and axial osteosarcoma. Similarities and differences between oral and maxillofacial osteosarcoma in humans are addressed.

Chondroma of the vertical ramus of the feline mandible.

A 5-year-old, castrated male, domestic shorthair cat presented with firm swelling in the right temporal region of the skull. The cat's jaws were almost locked in the closed position. Radiographs showed a mass with an irregular mineralized matrix superimposed on the caudal right mandible and temporomandibular joint. Surgical exploration revealed that the mass arose from the proximal part of the vertical ramus, which was removed, with the exclusion of the temporomandibular joint. It was possible to open the cat's mouth to nearly normal extension immediately after surgery. Recovery was uneventful - the cat has had no problem eating and no mass recurrence has been detected 3 years after surgery. Histological examination of the mass was consistent with chondroma. To the best of our knowledge, this is the first clinical and pathological description of a chondroma in cats, and one of the rare cases describing clinical presentation and management of primary bone tumours involving the vertical ramus of the feline mandible.

Use of samarium Sm 153 lexidronam for the treatment of dogs with primary tumors of the skull: 20 cases (1986-2006).

OBJECTIVE: To evaluate samarium Sm 153 lexidronam ((153)Sm-EDTMP) as a treatment option for dogs with bony tumors of the skull. DESIGN: Retrospective case series. ANIMALS: Dogs with multilobular osteochondrosarcoma (MLO) or osteosarcoma (OSA) of the skull. PROCEDURES: Veterinary Medical Teaching Hospital records from the Universities of Missouri and Florida from 1986 to 2006 were searched for dogs with primary skull tumors treated with (153)Sm-EDTMP. RESULTS: 25 dogs were initially evaluated, with 5 dogs subsequently excluded because of inadequate follow-up or unrelated death. Seven OSAs and 13 MLOs were diagnosed. Tumors involved the occipital and frontal bones (n = 10), zygomatic arch and maxilla region (6), palate (3), and mandible (1). No clinically important adverse effects related to (153)Sm-EDTMP treatment were documented. Of the 20 dogs evaluated 21 days after injection with (153)Sm-EDTMP, 4 had subjective improvement, 13 had progressive disease, and 3 had insufficient follow-up. On the basis of radiographic findings, metastasis was suspected in 1 dog; 16 dogs had no metastasis evident, and medical records were insufficient for 3 dogs. Survival time, defined as the (153)Sm-EDTMP injection date to the date of death, ranged from 3 to 1,314 days (median, 144 days). CONCLUSIONS AND CLINICAL RELEVANCE: The subjective improvement in 4 patients and lack of clinical evidence of adverse effects suggested that (153)Sm-EDTMP injection may be an option for the treatment of dogs with MLO or OSA of the skull when other treatments have failed or surgery is not possible.

Multilobular tumor of bone in an African wild dog (Lycaon pictus).

A 13-mo-old, captive-born, female African wild dog (Lycaon pictus) was presented with a progressively enlarging, firm mass on the dorsum of the head. Due to rapid tumor growth and the development of neurologic signs, elective euthanasia and a complete postmortem were performed 2 months after initial presentation. Histologic findings were similar in both antemortem biopsy and postmortem samples from the tumor and consisted of nodules of cartilage and/or bone separated by thin interconnected trabeculae that contained spindle-shaped cells, consistent with multilobular tumor of bone. Very few reports of tumors in the endangered African wild dog have been published to date. To the authors' knowledge, this is the first report of an osseous tumor in an African wild dog and the first report of a multilobular tumor of bone in a nondomestic canid.

Embryonal rhabdomyosarcoma in a Rothschild's giraffe (Giraffa camelopardalis rothschildi).

Abstract: A 3-yr-old male Rothschild's giraffe (Giraffa camelopardalis rothschildi) presented for acute swelling caudomedial to the left parietal horn. Following initial diagnostics and supportive treatment, the mass was surgically resected and intralesional chemotherapy was administered. Despite treatment, the giraffe's condition worsened and euthanasia was performed. Gross necropsy revealed neoplastic invasion and destruction of underlying parietal bone, adjacent horn base, and sinuses, and metastases in the tracheobronchial and mandibular lymph nodes and lung. Histologically, the tumor was composed of packets of anaplastic round cells. Immunohistochemical studies further characterized the tumor as an embryonal rhabdomyosarcoma. This is the first reported case of rhabdomyosarcoma in a giraffe.

Nasal osteoma in a dairy cow: a combined clinical, imaging and histopathological approach to diagnosis.

An 8-year-old Brown Swiss dairy cow was presented with unilateral epistaxis and mild inspiratory stridor. At that time endoscopic examination revealed a smooth-surfaced mass within the left nasal cavity. Biopsy samples were collected and a diagnosis of fibrosarcoma was made. Eighteen months later the animal developed severe respiratory distress that led to difficulties in feeding and consequently to emaciation and a dramatic drop in milk production. The cow was humanely destroyed and submitted for post-mortem examination. The head was subject to further investigation by radiography, computed tomography and magnetic resonance imaging. These techniques revealed a non-infiltrative, well-circumscribed mass of both radiodense and heterogeneously intense structures. Histopathological examination revealed a mass consisting of well-differentiated and interlacing bone trabeculae lined by osteoblasts and multinucleated osteoclasts. In contrast to the initial diagnosis, the later diagnostic approaches supported the diagnosis of osteoma.

Multilobular tumour of the caudal cranium causing severe cerebral and cerebellar compression in a dog.

Multilobular tumour of bone (MTB) is an uncommon tumour and is usually located in the skull. A 13-year-old mixed breed dog was presented with a two-week history of progressively worsening vestibular dysfunction and cognitive abnormalities; it appeared demented and showed asymmetric ataxia and hypermetria of all limbs. The owner opted to have the animal euthanised. Necropsy revealed a large mass occupying the right occipital, parietal and temporal bones, severely compressing the cerebellum and the right occipital lobe. Histologically, it was characterised by the presence of multiple lobules containing osteoid or cartilage and separated by fibrous septae, features typical of MTB. Lung metastases were evident. To our knowledge, this is the first report of an MTB causing both severe cerebral and cerebellar compression and the second detailed report of an MTB of the occipital bone. MTB should be included in the differential diagnosis of bone tumours as well as in cases with central vestibular disease.

Massive midline occipitotemporal resection of the skull for treatment of multilobular osteochondrosarcoma in two dogs.

CASE DESCRIPTION: Two 6-year-old male dogs were evaluated for removal of midline occipito-temporal multilobular osteochondrosarcomas. CLINICAL FINDINGS: Physical examination revealed mild ataxia in 1 dog and large masses of the central occipitotemporal portion of the skull in both dogs. Computed tomography, magnetic resonance imaging (MRI), or both revealed large bone-origin occipitotemporal masses with impingement of the brain and the sagittal and transverse venous sinuses. Three-dimensional contrast magnetic resonance image reconstruction delineated collateral venous circulation around the tumor and venous sinus occlusion in 1 dog. TREATMENT AND OUTCOME: Tumors in both dogs were surgically removed and the skull defects repaired with polymethyl methacrylate prostheses. Twenty-four hours after surgery, 1 dog had normal mentation, cranial nerve function, and conscious proprioceptive responses, whereas the other dog had depressed mentation but no neurologic deficits. Both dogs were discharged 4 days after surgery with normal mentation and no neurologic deficits. CLINICAL RELEVANCE: Findings suggested that MRI and computed tomography can play a key role in assessment of essential cortical collateral circulation when surgical removal of tumors is likely to result in bilateral disruption of transverse venous sinuses. Without robust collateral circulation and proper preoperative planning, removal of massive skull tumors in the midline occipitotemporal region will likely result in substantial morbidity or death. However, results in the 2 dogs reported here indicate the feasibility of removing such tumors with good outcomes in the presence of well-developed collateral venous drainage.