Osteosarcoma with widespread metastasis in a 1-year-old crossbred rabbit.

A 14-month-old female spayed, small crossbred rabbit presented for assessment of a small, hard subcutaneous nodule in the right axilla. Serum biochemistry showed markedly increased serum ALP activity. A whole-body CT revealed an aggressive, monostotic osteolytic, and productive lesion within the left alveolar process of the maxilla, with erosion of the alveolar bone and secondary premolar depression. Innumerable metastatic osseous masses were present throughout the body, including cerebral, pulmonary, hepatic, subcutaneous, and skeletal muscular metastases. Postmortem findings confirmed widespread, metastatic osteosarcoma, with the primary lesion within the left maxilla.

A modified full-thickness labial/buccal rotational flap reconstruction technique following bilateral rostral maxillectomy and nasal planectomy for resection of maxillary tumors: Technique and results in two dogs.

OBJECTIVE: To describe a naso-facial reconstruction technique following bilateral rostral maxillectomy and its functional and cosmetic outcomes. ANIMALS: Two dogs. STUDY DESIGN: Clinical case series. METHODS: Two dogs were presented with a right rostral maxillary mass. Preoperative biopsy and staging revealed a biologically high-grade and histologically low-grade fibrosarcoma (Hi-Lo FSA). A combined nasal planectomy and radical bilateral rostral maxillectomy was performed sparing the labial/buccal mucocutaneous flaps bilaterally. Surgery resulted in asymmetry of the width of the flaps; the narrower flap was rotated medially to reconstruct the lip and create an oral vestibule. The wider flap was rotated medially to cover the remaining dorsolateral opening of the nasal conchae. The flaps overlapped in a parallel manner, discretely concealing the nasal passages, and separating them from the oral cavity. Hemorrhage occurred in both dogs, with one dog requiring a blood transfusion postoperatively. RESULTS: Oral Hi-Lo FSA with tumor-free margins was confirmed in both dogs. Both dogs recovered uneventfully within 4 weeks. Owners reported being very satisfied with the functional (return to normal exercise/activities and uncompromised respiration) and cosmetic outcomes. Based on the owners' telephone follow up, no tumor recurrence was noted at 15 (Dog 1) and 6 (Dog 2) months postoperatively. CONCLUSION: The full-thickness bilateral labial/buccal rotational flaps were used successfully to reconstruct the rostral maxilla, external nose and facial defects involving the nasal cavity. The technique resulted in acceptable functional and cosmetic outcomes and can be considered for naso-facial reconstruction in selected cases.

Treatment of leiomyosarcoma in a tiger (Panthera tigris) with stereotactic radiotherapy.

A 10-year-old male captive tiger (Panthera tigris) developed right-sided facial asymmetry and enlargement. Computed tomography revealed a destructive mass of the right maxillary bone with right nasal cavity involvement. Histopathology indicated a spindle cell sarcoma. A single fraction of 22 Gy using stereotactic radiotherapy was prescribed. After treatment, the facial conformation returned to normal and the tiger resumed normal behavior. Diagnostics 4 months later indicated severe metastatic disease. Humane euthanasia and necropsy were performed. This is the first case utilizing stereotactic radiotherapy for the treatment of cancer in a tiger.

Extensive Maxillary Odontomas in 2 Dogs.

Two immature male dogs were presented for the treatment of extensive maxillary compound odontomas. In both cases, clinical evaluation and diagnostic imaging revealed extensive lesions invading and displacing anatomical structures of the maxilla. Histopathology confirmed the diagnoses in both cases. One dog was treated with partial rostral maxillectomy, and the other dog was treated with enucleation of the cystic lining and removal of tooth-like structures through a lateral rhinotomy utilizing an intraoral approach. This report illustrates the growth potential of maxillary compound odontomas in 2 dogs and highlights their subclinical appearance and excellent prognosis despite their extensive nature.

Elodontoma in Two Guinea Pigs.

Elodontoma was diagnosed in two pet guinea pigs, one involving a maxillary premolar tooth and the other affecting a mandibular incisor tooth. Diagnostic imaging, including radiographs, computed tomography, and oral endoscopy was performed in order to quantify dental disease. Diagnostic imaging was also used to guide treatment of acquired dental disease, which included intraoral restoration of normal occlusal plane and tooth extraction using an extraoral approach. These are the first histologically confirmed cases of elodontoma in guinea pigs.

A novel technique for ventral orbital stabilization: the masseter muscle flap.

Loss of the caudal maxilla and ventral orbit after tumor resections can have negative functional and esthetic influences on the eye involved. This article reports on a case of a caudal maxillary acanthomatous ameloblastoma involving the ventral orbit that was resected and stabilized with a masseter muscle flap. The masseter muscle flap was generated from the superficial belly of the masseter muscle in order to close a defect in the orbital rim, created by a caudal maxillectomy. None of the published complications such as enophthalmos, excessive lacrimation, globe deviation, or strabismus were noted, 8 months following the procedure. The only clinical sign present at the time of re-evaluation was mild lacrimation. The authors propose the use of a masseter muscle flap as a viable technique in stabilizing the ventral orbit after caudal maxillectomy and ventral orbitectomy, preventing the complications associated with this surgery.

Clinical, histologic, and computed tomographic features of oral papillary squamous cell carcinoma in dogs: 9 cases (2008- 2011).

Medical records of dogs diagnosed with oral papillary squamous cell carcinoma between December 2008 and April 2011 were reviewed. Information abstracted included signalment, tumor location, tumor size, computed tomographic (CT) features, evidence of metastatic disease based on cytologic examination of lymph node aspirates and thoracic radiography, treatment, surgical margins, histologic features, and treatment outcome. Dogs included in the study were all sexually altered, predominantly large breed dogs with a mean age of 3.9-years (range, 0.5 to 9.0-years). The most common location was the rostral maxilla. Invasion of underlying bone and lymphadenopathy were evident on CT imaging in most dogs. No evidence of metastasis was found on mandibular lymph node cytology and thoracic radiography. Histologic analysis revealed similar morphologic findings for all surgically resected tumors. Surgical excision with 1-2 cm margins was complete in all cases, with a mean tumor-free interval of 12.1-months.

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.

Maxillary ameloblastic fibroma in a dog.

A 4-year-old spayed female Golden Retriever was presented for evaluation of a rostral maxillary gingival mass. An en bloc resection was performed after histologic diagnosis of ameloblastic fibroma from an incisional biopsy specimen. Histologically, the tumor was composed of (1) poorly differentiated vimentin-positive mesenchymal cells that surrounded islands and (2) thin anastomosing trabeculae of odontogenic epithelium that variably coexpressed pancytokeratin and vimentin. To the authors' knowledge, this is the first report of ameloblastic fibroma in a dog. The clinical, radiographic, and histologic findings in this case are compared to those in other domestic animals and humans.

Oral masses in two cats.

Incisional biopsies from the oral cavity of 2 adult cats were submitted for histological investigation. Cat No. 1 showed a solitary well-circumscribed neoplasm in the left mandible. Cat No. 2 demonstrated a diffusely infiltrating neoplasm in the left maxilla. Both tumors consisted of medium-size epithelial cells embedded in a fibrovascular stroma. The mitotic index was 0 to 1 mitosis per high-power field. The epithelial cells showed an irregular arrangement forming nests or streams in cat No. 1, whereas a palisading growth was noted in cat No. 2. Both tumors, especially that of cat No. 1, showed multifocal accumulations of amyloid as confirmed by Congo red staining and a distinct green birefringence under polarized light, which lacked cytokeratin immunoreactivity as well as and AL and AA amyloid immunoreactivity. In addition, the amyloid in cat No. 2 was positive for the odontogenic ameloblast-associated protein, formerly termed APin. In sum, both cats suffered from an amyloid-producing odontogenic tumor, but their tumors varied with respect to morphology and type of amyloid produced.

Comparison of the effects of tramadol, codeine, and ketoprofen alone or in combination on postoperative pain and on concentrations of blood glucose, serum cortisol, and serum interleukin-6 in dogs undergoing maxillectomy or mandibulectomy.

OBJECTIVE: To compare analgesic effects of tramadol, codeine, and ketoprofen administered alone and in combination and their effects on concentrations of blood glucose, serum cortisol, and serum interleukin (IL)-6 in dogs undergoing maxillectomy or mandibulectomy. ANIMALS: 42 dogs with oral neoplasms. PROCEDURES: 30 minutes before the end of surgery, dogs received SC injections of tramadol (2 mg/kg), codeine (2 mg/kg), ketoprofen (2 mg/kg), tramadol+ketoprofen, or codeine+ketoprofen (at the aforementioned dosages). Physiologic variables, analgesia, and sedation were measured before (baseline) and 1, 2, 3, 4, 5, and 24 hours after surgery. Blood glucose, serum cortisol, and serum IL-6 concentrations were measured 1, 3, 5, and 24 hours after administration of analgesics. RESULTS: All treatments provided adequate postoperative analgesia. Significant increases in mean+/-SD blood glucose concentrations were detected in dogs receiving tramadol (96+/-14 mg/dL), codeine (120+/-66 mg/dL and 96+/-21 mg/dL), ketoprofen (105+/-22 mg/dL), and codeine+ketoprofen (104+/-16 mg/dL) at 5, 1 and 3, 5, and 3 hours after analgesic administration, respectively, compared with preoperative (baseline) values. There were no significant changes in physiologic variables, serum IL-6 concentrations, or serum cortisol concentrations. Dogs administered codeine+ketoprofen had light but significant sedation at 4, 5, and 24 hours. CONCLUSIONS AND CLINICAL RELEVANCE: Opioids alone or in combination with an NSAID promoted analgesia without adverse effects during the 24-hour postoperative period in dogs undergoing maxillectomy or mandibulectomy for removal of oral neoplasms.

The use of rim excision as a treatment for canine acanthomatous ameloblastoma.

This study reviews rim excision as a treatment for canine acanthomatous ameloblastomas (CAA) in dogs with <3 mm of bone involvement. Removal of a canine tooth was involved in 47% of the cases; 33% cases involved the caudal dentition. Follow-up ranged from 3 months to 5 years. No evidence of recurrence was seen. Client satisfaction with cosmesis and the animal's ability to masticate was judged to be good. With appropriate case selection, rim excision appears to be a viable option for CAA and results in improved dental occlusion, cosmesis, and no evidence of epulis recurrence.

Intraosseous maxillary hemangioma in an immature Bassett Hound.

A 6-month-old Bassett Hound dog presented for evaluation of recurrent oral bleeding and a right maxillary swelling. Oral examination revealed right maxillary enlargement extending from the level of the right maxillary canine tooth to the area of the second and third premolar teeth. A discolored persistent right maxillary deciduous canine tooth and gingival inflammation was noted. Biopsies taken at the time of extraction of the persistent deciduous canine tooth resulted in significant hemorrhage and a biopsy report of reactive bone. The right maxillary enlargement did not resolve following the extraction procedure and empirical antimicrobial therapy. The owner elected euthanasia and post-mortem evaluation. Histopathologic assessment provided a diagnosis of maxillary hemangioma.

Odontoameloblastoma with extensive chondroid matrix deposition in a guinea pig.

Odontoameloblastomas (previously incorporated within ameloblastic odontomas) are matrix-producing odontogenic mixed tumors and are closely related in histologic appearance to the 2 other types of matrix-producing odontogenic mixed tumors: odontomas and ameloblastic fibro-odontomas. The presence or absence of intralesional, induced non-neoplastic tissue must be accounted for in the diagnosis. Herein we describe a naturally occurring odontoameloblastoma with extensive chondroid cementum deposition in a guinea pig ( Cavia porcellus). Microscopically, the mass featured palisading neoplastic odontogenic epithelium closely apposed to ribbons and rings of a pink dental matrix (dentinoid), alongside extensive sheets and aggregates of chondroid cementum. The final diagnosis was an odontoameloblastoma given the abundance of odontogenic epithelium in association with dentinoid but a paucity of pulp ectomesenchyme. Chondroid cementum is an expected anatomical feature of cavies, and its presence within the odontoameloblastoma was interpreted as a response of the ectomesenchyme of the dental follicle to the described neoplasm. Our case illustrates the inductive capabilities of odontoameloblastomas while highlighting species-specific anatomy that has resulted in a histologic appearance unique to cavies and provides imaging and histologic data to aid diagnosis of these challenging lesions.

Maxillofacial rhabdomyosarcoma in the canine maxillofacial area.

Three dogs had a diagnosis of maxillofacial rhabdomyosarcoma. These dogs were treated with surgery and/or radiotherapy, and had poor clinical responses. The tumor tissues in all three cases were observed around the upper premolar teeth with ulcerative lesions and CT examinations in each case revealed extensive bony involvement into the maxilla. Two cases were subjected to surgical excision of the tissues, followed by an external radiation therapy. The other case was only treated with palliative radiation. Outcomes of the treatment of all the cases were quite poor because of the invasive and refractory nature of the tumor cells, leading to the local recurrence and lung metastasis early in the clinical course. All dogs died within two months of the first admission.

Cosmetic rostral nasal reconstruction after nasal planum and premaxilla resection: technique and results in two dogs.

OBJECTIVE: To describe a novel reconstructive technique after nasal planum and premaxilla resection. STUDY DESIGN: Case report. ANIMALS: Dogs (n=2) with squamous cell carcinoma (SCC) of the nasal planum. METHODS: A 9-year-old neutered female Labrador retriever (dog 1) and an 11-year-old neutered male Golden retriever (dog 2) had resection of the nasal planum and premaxilla for treatment of locally invasive SCC. Reconstruction of a nasal planum facsimile was based on use of the nonhaired pigmented margins of bilateral labial mucocutaneous rotation-advancement flaps. RESULTS: Reconstruction of the premaxilla by construction of a nasal planum facsimile resulted in uncomplicated wound healing and improved cosmesis. There was no tumor recurrence at 1290 (dog 1) and 210 (dog 2) days after surgery. CONCLUSION: Reconstruction of a nasal planum facsimile was successfully performed without complications in 2 dogs with high owner satisfaction with cosmetic appearance. CLINICAL RELEVANCE: This technique represents a significant advancement in surgical cosmetic outcome, may potentially reduce postoperative complications, and should be considered for dogs requiring nasal reconstruction after nasal planum resection with premaxillectomy.

Maxillary unicystic ameloblastoma in a 6-week-old filly evaluated with computed tomography.

CASE REPORT: A 6-week-old Thoroughbred filly was presented for evaluation of an expansile mass overlying the right nasal passage and causing respiratory stertor. On skull radiographs, there was a loculated, soft tissue-opaque mass identified dorsal to the right upper premolars and effacing the right nasal cavity. Computed tomography (CT) revealed a locally extensive mass with relatively benign characteristics located centrally on the tooth root apices of the deciduous second premolar (506). The mass extended axially into the right nasal cavity, occluding the meatuses and causing displacement of the nasal septum to the left. CLINICAL OUTCOME & SIGNIFICANCE: Surgical excision was not deemed feasible with an athletic future in mind and the owners elected to euthanase the filly. Histopathologically, the mass was consistent with unicystic ameloblastoma and was lined intermittently with palisading, columnar basal cells (ameloblast-like cells) overlying a zone containing stellate cells in loose stroma. To the authors' knowledge this is the first report of a CT scan of an equine ameloblastoma. Although histopathology was essential for definitive diagnosis, CT clearly defined the origin of the mass and identified its locally extensive, cystic nature, which enabled informed decisions to be made.