Computed tomographic characteristics of multilobular tumor of bone involving the cranium in 7 dogs and zygomatic arch in 2 dogs

Multilobular osteochondrosarcoma of the vertical ramus of the mandible in a cat

A 7-year-old castrated male domestic shorthair cat presented with locked jaw syndrome and firm swelling in the right temporal region of the skull. A computed tomography (CT) scan showed a heavily calcified mass of the right coronoid process of the mandible with a popcorn appearance, consistent with a multilobular osteochondrosarcoma. The zygomatic arch was displaced laterally and ventrally due to the mass effect. The temporomandibular joint was not involved. Surgical treatment was performed and consisted of the removal of the zygomatic arch and the vertical ramus of the mandible. It was possible to open the mouth normally immediately after surgery. Recovery was uneventful. Histological examination of the mass confirmed multilobular osteochondrosarcoma. This type of tumor is rarely encountered in dogs, and a literature search reveals only two cases in cats: one arising from the skull and one from thoracic wall. This case report documents the first description of a multilobular osteochondrosarcoma of the mandible in a cat.

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.

Multilobular tumor of bone on the forehead of a guinea pig

Multilobular tumor of bone (MLTB) is an infrequent, slow-growing, bone neoplasm formed predominantly on the head. These tumors can behave as malignant neoplasms clinically and pathologically and can metastasize occasionally. No cases of MLTB in rodents have been reported, to our knowledge. We describe a novel case of an MLTB in a guinea pig. An adult guinea pig had an exophytic mass fixed on the frontal bone, maxilla, and nasal bone. On radiography, the mass had a spherical contour and variable density and was formed on the surface of the cranial bones. The mass was excised surgically. The cut surface was light-yellow to milky-white and had a granular texture with fine fibrous septa. Histologically, the neoplasm had a multilobular pattern, which consisted of many islands of bone and/or cartilage matrix surrounded by small cells and separated by fibrous septa, which closely resembles the equivalent neoplasm in dogs.

Imaging in Non-neurologic Oncologic Treatment Planning of the Head and Neck

Imaging is critical for the diagnosis and staging of veterinary oncology patients. Although cytology or biopsy is generally required for diagnosis, imaging characteristics inform the likelihood of a cancer diagnosis, can result in a prioritized list of differentials that guide further staging tests, and assist in the planning of surgery, radiation, and chemotherapy options. Advanced imaging, such as CT and MRI, can better define the extent of disease for surgical and radiation planning for head and neck cancer cases in particular. Additionally, new imaging technologies are continually being translated into veterinary fields, and they may provide more options for cancer patients as they become more widely available.

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.

Comparison of standard radiography and computed tomography in 21 dogs with maxillary masses

Imaging of patients with oral cancer is required to determine tumor extension in order to assist in prognosis and surgical planning. Conventional screen-film radiography (SFR) used to be the most common method for oral assessment, but computed tomography (CT) has become more available and is being used for obtaining complementary information. CT examinations eliminate superimposition by acquiring cross-sectional images of the region of interest. The objective of this study was to determine the diagnostic value of SFR compared with CT examinations for evaluation of oral masses in dogs. Twenty-one dogs received head and thorax SFR, and pre- and post-contrast head CT. Bony changes were observed in 80.9% and 95.2% of the cases in SFR and CT studies, respectively. Invasion of adjacent structures (i.e. nasal cavity, frontal and sphenoidal sinuses, orbit, maxillary recess, nasopharynx) was observed in only 30% of cases with SFR while CT showed 90.4% involvement. CT is an important preoperative examination modality and is more effective in identifying bone changes and tumor invasion of adjacent structures compared with SFR.

Multilobular Tumor of Bone in the Mandible of a Dog

An 8-year-old Siberian husky dog was presented for a mass involving the rostral mandible. Intraoral radiographs demonstrated diffusely irregular bone and displacement of all mandibular incisor teeth. The mass was diagnosed as a grade I multilobular tumor of bone based on incisional biopsy. A bilateral rostral mandibulectomy was performed with tumor negative margins. Oral examination at 14-months following surgery indicated normal healing with minimal side effects and no evidence of tumor recurrence.

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.

Reconstructive cranioplasty using a porcine small intestinal submucosal graft

A six-year-old border collie was presented with a solid mass on the dorsal cranium. Histological examination showed the mass to be a multilobular tumour of bone. A magnetic resonance imaging scan confirmed deformation of the dorsal cranium with compression of the cerebral hemispheres. A craniotomy was performed to excise the mass and overlying skin, resulting in a substantial deficit of calvarium and skin. A cranioplasty using a small intestinal submucosal (SIS) graft was performed to reconstruct the calvarial defect. A local myocutaneous advancement flap was elevated and positioned over the cranioplasty to close the skin deficit. The outcome of this reconstruction was aesthetic and functional. The small intestinal submucosal graft provided satisfactory mechanical support and was a suitable physical barrier in place of the calvarial bone. Histological examination of the small intestinal submucosal graft 128 days after implantation showed that the graft had been replaced by a dense network of collagenous tissue, with small focal areas of partially mineralised woven bone merging with a fibrocartilaginous matrix of the deeper margin. Histological examination also confirmed regrowth of the multilobular tumour of bone in the region of the small intestinal submucosal graft indicating that it is only a suitable implant if adequate surgical margins are obtained.

Advanced imaging for veterinary cancer patients

This article presents an update on the recent advances made in veterinary advanced imaging specifically with regard to cross-sectional modalities (CT and MRI) and nuclear medicine (positron emission tomography [PET] and PET/CT). A brief summary of technical improvements and a review of recent literature are included to provide an overview of the progress made in this important element of the practicing veterinary oncologist's repertoire. An in-depth summary of PET is also included to introduce the technical aspects and potential clinical and research applications of this novel imaging modality in veterinary medicine.

Comparison of computed tomographic images of normal cranial and upper cervical lymph nodes with corresponding E12 plastinated-embedded sections in the dog

To document normal lymph nodes on computed tomographic images, 102 scans were reviewed of dogs that had computed tomography (CT) of the head and upper cervical region. If lymph nodes were identified, symmetry, density, homogeneity, and size, as well as the relation to the surrounding fat tissue were noted. CT images with distinct asymmetric, enlarged, and obliterated lymph nodes were excluded. To improve the detailed anatomical topography, corresponding E12 plastinated-embedded sections of a dog were used. Compared with muscle tissue, normal lymph nodes were slightly hypodense and had a homogeneous parenchyma. Mandibular and retropharyngeal lymphocentres could be seen consistently and CT proved to be a useful method both to detect their presence and to assess their morphology. It was not possible to identify the parotid lymph node consistently because of the lack of tissue contrast at the lymph node-gland interface.

Multilobular tumour of bone of the thoracic wall in a cat

Multilobular tumour of bone is a rare neoplasm of the skull in middle-aged, medium-to-large breed dogs even if a few cases have also been described in cats and one horse. The aim of the present paper is to show both the computed-tomography features and the pathological findings of the above neoplasm affecting the thoracic wall of a cat. To the best of the authors' knowledge, such anomalous tumour localisation has never been reported and imaged in feline medicine.

Computed tomography in small animals – Basic principles and state of the art applications

Since its clinical introduction, computed tomography (CT) has revolutionized veterinary medicine and is considered to be one of the most valuable tools for the imaging work-up of neurological, oncological and orthopaedic canine and feline patients. In small animals with acute trauma, particularly those involving complex anatomic areas such as the head, spine or pelvis, CT has been established as a standard imaging method. With the increasing availability of radiation therapy in veterinary medicine, CT has also become the principal tool to stage a tumour, assess response, and guide radiation therapy. The increasing availability of helical CT in veterinary medicine has allowed novel techniques such as spiral CT angiography and high-resolution CT. This review provides a brief overview of the historical and technical development of CT and literature reviews of the major clinical CT applications in small animals such as intracranial and extracranial lesions, the spine, the appendicular skeleton, and abdominal and thoracic diseases.

Common malignant musculoskeletal neoplasms of dogs and cats

Malignancies of the musculoskeletal system in dogs and cats can be categorized as either primary or metastatic within the bony or soft structures that comprise the musculoskeletal system. By far, the most common tumor that affects the musculoskeletal system in dogs is osteosarcoma. The most common tumors that affect the musculoskeletal system in cats are injection site sarcomas. These tumors are locally infiltrative; whereas up to 25% metastasize, most animals die from our inability to control local disease. The aim of this article is to provide a brief review of the biologic behavior of and treatment recommendations for common tumors of the musculoskeletal system, excluding the oral and nasal cavities.

Multilobular osteochondrosarcoma of the hard palate in a dog

A 14-year-old castrated male Rhodesian Ridgeback was presented with a history of sneezing and epistaxis. Diagnostic procedures included physical examination, regional and thoracic radiography, computed tomography and histological examination of an incisional biopsy. A multilobular osteochondrosarcoma of the hard palate with pulmonary metastases was diagnosed. Surgical resection of the primary tumour was achieved with clean margins and the defect was repaired using bilateral mucosal transposition flaps from the lips. Wound dehiscence and oesophageal stricture were postoperative complications, but these resolved with treatment. A long-term survival time of 14 months resulted, with good quality of life and function during this time.

Imaging of the canine and feline temporomandibular joint: a review

The radiographic anatomy of the temporomandibular joint in the dog and cat is described in dorsoventral and oblique projections. The positioning for different oblique views in conventional radiography and technical details of computed tomography are reviewed. Typical radiographic features of craniomandibular osteopathy, dysplasia, luxation, subluxation, fractures, ankylosis, degenerative joint disease, infection, and neoplasia involving the temporomandibular joint are discussed.