Ameloblastic fibro-odontosarcoma with mandibular bone invasion and regional lymph node metastasis in a cat: case report.

Odontogenic tumours are uncommon neoplasms in domestic animals, mostly solitary and locally infiltrative, but rarely metastatic. We report the case of a 13-year-old neutered male cat presented with a mandibular gingival neoformation. A computed tomography scan revealed an irregular neoformation with marked post-contrast enhancement, associated with lysis of the incisive bone and mandibular symphysis. Histologically, the oral mucosa and mandibular bone were infiltrated by a neoplasm consisting of a mixed population of odontogenic epithelium admixed with bundles of odontogenic ectomesenchyme, multifocally associated with hard tissue deposition. A spindloid cell component had metastasized to the right mandibular lymph node. The epithelial component was immunoreactive for cytokeratins (CK) 5/6, CK 14, pancytokeratin (CK AE1/AE3) and p63; the ectomesenchymal component was vimentin positive. A final diagnosis of ameloblastic fibro-odontosarcoma with bone invasion and lymph node metastasis was made. The findings indicate the metastatic potential of this rare tumour.

A rare case report of extensive mandibular osteoma corrected by unilateral mandibulectomy: Cytological, radiological, and pathological investigation.

Background: Osteoma is a benign bone tumor that rarely affects animals. The most common bones involved with this tumor included the mandible, maxillofacial bones, and nasal sinuses. Definitive diagnosis is based on pathology findings which allow for differentiation with other bone lesions. Case Description: The patient, a 5-year-old intact male Mongrel dog presented with a huge mandibular mass that involved both the right and left mandible, and led to dental occlusion. The radiography was performed and depicted the intense mass with a well-demarcated edge, a short transitional zone between normal and abnormal bone, and a smooth rounded radiopaque appearance. The investigation according to the fine needle aspiration showed the presence of oval to spindle shape cells with poorly malignancy criteria, fatty cells, reactive osteoblasts, and osteoclasts based on a population of spindle-shaped cells, and low numbers of degenerated neutrophils, bacteria, and few macrophages. Then, the radiographic assessments and cytology findings demonstrated the osteoma and were referred for surgical intervention. A unilateral mandibulectomy was performed, and the lesion was sent to the histopathology laboratory. The histopathology evaluation showed osteocyte proliferation without malignancy features. The osteoblast cells also showed no atypical proliferation that endorses the osteoma tumor. Conclusion: Although mandibular and maxillofacial bone resection in small animals have different tolerations, this patient became a candidate for surgery for future better nutrition and prevention of facial deformity and dental malocclusion. Follow-up after osteoma is one of the most necessary post-operation treatments to check the regeneration of the mass. There are considerable data in this report that should regard this tumor as a possible differential diagnosis for mandibular tumors.

Three Cases of Mandibular Ossifying Fibroma in Cattle.

Neoplastic masses were evaluated in the rostral region of the mandible of three young adult cattle. In all three cases, the masses were macroscopically large, firm, ulcerated, infiltrative, whitish and solid, and led to tooth displacement and loss. Radiographically, the neoplastic masses were intraosseous and radiolucent with foci of radiopacity. Loss of radiopacity due to bone necrosis was seen in the mandibular bone adjacent to the neoplasms. Histologically, well-differentiated, infiltrative non-encapsulated mesenchymal neoplastic proliferation replaced the mandibular bone and extended to the oral mucosa in all three cases. The neoplastic cells had scant cytoplasm and fusiform or oval hyperchromatic nuclei with loose chromatin, and were arranged in bundles in various directions. Within the neoplastic tissue, there were mineralized bone trabeculae and unmineralized osteoid, lined by a layer of osteoblasts and osteocytes within the lacunae. The pre-existing bone tissue adjacent to the neoplasm had areas of necrosis and osteoclasis of variable extent and intensity. Based on the macroscopic, radiographic and microscopic findings, a diagnosis of mandibular ossifying fibroma was established in all three cattle.

Ameloblastic carcinoma in horses: case report and literature review.

Ameloblastic carcinoma is a malignant odontogenic neoplasm that has been reported only rarely in veterinary species. A 16-y-old Arabian crossbred mare was presented for evaluation of a hard mass on the body of the mandible, with evidence of osteolysis on radiographs. Incisional biopsies revealed an invasive neoplasm comprised of spindloid epithelial cells with a high mitotic count and partial dual cytokeratin-vimentin immunoreactivity. The horse was euthanized because of rapid tumor progression 3 mo after presentation. Postmortem evaluation revealed partial obliteration of the mandible by a large, firm-to-hard, tan, locally destructive and invasive mass with no gross or histologic evidence of metastasis. Postmortem histology revealed a poorly differentiated epithelial neoplasm with variably prominent features suggestive of odontogenic histogenesis: a plexiform ribbon architecture, infrequent basilar palisading with antibasilar nuclei, rare basilar cytoplasmic clearing, subepithelial matrix hyalinization, and partial dual cytokeratin-vimentin immunoreactivity. Features of malignancy included regions of necrosis, pronounced cellular atypia, a high mitotic count, extensive tissue invasion and local tissue destruction, and extension of neoplastic cells beyond the margins of the mandibular bone. Collectively, these features are most consistent with mandibular ameloblastic carcinoma. Including our case described here, ameloblastic carcinoma has been reported in only 5 horses. The microscopic features reported most consistently are dual cytokeratin-vimentin immunoreactivity, a high mitotic count, and basilar palisading. Ameloblastic carcinoma should be considered as a differential diagnosis for rapidly growing, locally invasive masses arising from the dentate jaw of horses.

Differential diagnosis for a mandibular mass - a rare case of an odontoameloblastoma in a red deer (Cervus elaphus elaphus).

BACKGROUND: Mandibular masses caused by inflammatory processes due to bacterial infections, most common with Actinomyces bovis, are well known in herbivors. This case represents a rare differential diagnosis to common inflammatory processes which cannot be distinguished from neoplasia without detailed histopathological examination. CASE PRESENTATION: A large unilateral mandibular mass of a free-ranging female adult red deer (Cervus elaphus elaphus) was submitted for pathological examination. The animal had been shot due to its poor body condition. Grossly, the mandibular mass showed gingival ulceration and necrosis. Histologically, irregular strands and islands of odontogenic epithelial cells and a matrix of dentin and osteoid-like material were found, leading to the diagnosis of an odontogenic tumor. Considering the animal's age the tumor was classified as odontoameloblastoma with secondary chronic purulent osteomyelitis. CONCLUSIONS: Odontogenic tumors are rare in domestic and wildlife species and so far have not been reported in red deer. In addition to the more common inflammatory processes of the mandibula and other neoplastic diseases of the oral cavity, odontogenic tumors represent a rare differential diagnosis that must be kept in mind especially when masked by inflammatory lesions.

Spontaneous Regression of a Mandibular Plasmacytoma in a Juvenile Dog: A Case Report.

A 4 mo old female Finnish lapphund presented for further investigation of a swelling of the right rostral mandible. A computed tomography scan showed the swelling to be an expansile and osteolytic mandibular lesion. Histopathology revealed a poorly differentiated, moderately well-demarcated, unencapsulated, highly infiltrative round cell neoplasm, and immunohistochemistry was supportive of a plasmacytoma. Performance of a rostral partial mandibulectomy was initially discussed with the owners, but the lesion improved spontaneously both clinically and on repeated computed tomography scanning before surgery could be performed. It subsequently almost completely resolved 6 mo after diagnosis. Hypotheses for spontaneous regression of the lesion are discussed and the human literature is briefly reviewed.

[Spindle-cell sarcoma in the mandibular area of a 5-year-old Holstein Friesian cow]. / Spindelzelliges Sarkom am Unterkiefer einer 5 Jahre alten Holstein-Friesian-Kuh.

A 5-year-old German-Holstein cow was presented with a swelling of the head which had been present for 3 months. Clinical examination revealed a 15 × 20 × 15 cm firm mass on the right side of the head. The cow was lethargic, showed an extended head and neck posture, nasal stridor, mucopurulent nasal discharge, and inspiratory dyspnea with labored breathing. Furthermore, dysphagia as well as moderate to strong salivation were evident. Radiological examination revealed a diffuse, poorly defined mass with different densities overlying the bony structures of the skull. Endoscopic examination confirmed a space-occupying mass in the pharyngeal area. Sonographically, the swelling presented as a compact, clearly inhomogeneous tissue with focal areas of different echogenicity. Necropsy of the euthanized cattle confirmed the presence of a tumor that had already metastasized to the lungs. Histologically and immunohistochemically, the tumor presented as a spindle-cell, vimentin-expressing soft tissue sarcoma, most likely compatible with fibrosarcoma.

Diagnosis and Treatment of an Odontogenic Epithelial Tumor in a Dog With Features of Squamous Odontogenic Tumor.

A 9-year-old standard poodle presented for a comprehensive oral health assessment and treatment, at which time a left rostral mandibular swelling was recognized. The mass was biopsied and eventually excised by a left rostral mandibulectomy en bloc resection. Histopathology supported the diagnosis of a benign, intraosseous, epithelial tumor that was otherwise unclassified. The clinical, radiological, and histological features of this case are similar to those reported for squamous odontogenic tumor (SOT) in humans. This case study relays the diagnosis, treatment, and follow-up of the first SOT-like tumor in a dog.

Immunohistochemical Profile of Ameloblastic Carcinoma Arising from an Amyloid-Producing Odontogenic Tumour in a Miniature Dachshund.

A 13-year-old female miniature dachshund was presented with a centrally-located sublingual mass in the rostral mandibular region. The focally ulcerated growth completely covered the left (305) and right (405) premolar teeth and partially covered the right canine teeth (404). A punch biopsy sample revealed neoplastic proliferation of odontogenic epithelium arranged in irregular cords with frequent comedo-like necrosis. Following the initial diagnosis of ameloblastic carcinoma, a bilateral rostral hemimandibulectomy was performed. Although the detailed examination of the resected mass was consistent with the initial diagnosis, it also contained birefringent congophilic, amelogenin-labelled amyloid deposits similar to an amyloid-producing odontogenic tumour (APOT) in 30-40% of the mass, in continuity with the ameloblastic carcinoma. All neoplastic cells had diffuse moderate expression of cytokeratin (CK) AE1/AE3 and CK5, diffuse mild expression of CK14 and multifocal moderate expression of CK19. Because the APOT-like growth in the mass was histologically benign, the tumour was diagnosed as an ameloblastic carcinoma arising from an APOT.

Mixed odontogenic tumors in four young dogs: ameloblastic fibroma and ameloblastic fibro-odontoma.

Ameloblastic fibroma (AF) and ameloblastic fibro-odontoma (AFO) are mixed odontogenic tumors (odontogenic tumors with induction) that are reported only rarely in dogs. These tumors are histologically complex and, to a degree, recapitulate the early stages of tooth development, comprising 2 types of tissue: neoplastic odontogenic epithelium, and induced ectomesenchyme (dental pulp). AFOs are distinguished from AFs by the additional presence of hard dental matrices such as dentin. Herein, we describe the key diagnostic features of AF and AFO in 4 young dogs.

Management of an extensive equine juvenile ossifying fibroma by rostral mandibulectomy and reconstruction of the mandibular symphysis using String of Pearls plates with cortical and cancellous bone autografts.

OBJECTIVE: To describe a surgical technique for rostral mandibulectomy and reconstruction of the mandibular symphysis. STUDY DESIGN: Case report. ANIMAL: One 5-month-old warmblood cross filly. METHODS: A preoperative diagnosis of a juvenile ossifying fibroma was made on the basis of clinical appearance and was later confirmed via histology. The tumor was large, rapidly growing and extending to the caudal aspect of the mandibular symphysis. Computed tomography was performed for surgical planning. The tumor was excised by performing a mandibulectomy caudal to the symphysis. The mandibular symphysis was reconstructed with String of Pearls (SOP) plates. Cortex screws placed in lag fashion, a cortical bone graft from one of the mandibles and a cancellous graft harvested from the tuber coxae. RESULTS: At 9 months of age there was no sign of tumor reoccurrence, the implants were removed because of infection and the mandible had formed a new stable symphysis. The horse was able to prehend food and masticate normally. The owner was pleased with the cosmetic and functional outcome. CONCLUSION: The described surgical technique is a viable option for mandibulectomy and reconstruction of the mandibular symphysis. The technique provided adequate stability for healing to occur in the face of infection. CLINICAL SIGNIFICANCE: Neoplasia and other conditions affecting the entire mandibular symphysis can be treated by complete surgical excision and reconstruction.

Diagnostic accuracy of contrast-enhanced computed tomography for assessment of mandibular and medial retropharyngeal lymph node metastasis in dogs with oral and nasal cancer.

The diagnostic accuracy of contrast-enhanced CT for detection of cervical lymph node metastasis in dogs is unknown. The purpose of this retrospective, observational, diagnostic accuracy study was to assess the efficacy of CT for detection of mandibular and medial retropharyngeal lymph node metastasis in dogs. Histopathology of dogs with cancer of the head, CT and bilateral mandibular and medial retropharyngeal lymphadenectomy was reviewed. A single radiologist measured lymph nodes to derive short axis width and long-short axis ratios. Two blinded radiologists separately assessed lymph node margins, attenuation and contrast enhancement and each provided a final subjective interpretation of each node site as benign or neoplastic. Where radiologists' opinions differed, a consensus was reached. Sensitivity, specificity and accuracy were calculated for mandibular and medial retropharyngeal sites. Agreement between radiologists was assessed. Fisher's exact test and the Kruskal-Wallis H-test were used to assess associations between variables. Forty-one primary tumours were recorded in 40 dogs. Metastasis to mandibular or retropharyngeal lymph nodes occurred in 16 out of 40 dogs (43/160 nodes). Agreement between radiologists was almost perfect for margination, attenuation and enhancement, strong for interpretation of mandibular lymph node metastasis, and weak for interpretation of medial retropharyngeal lymph node metastasis. Sensitivity of CT was 12.5% and 10.5%, specificity was 91.1% and 96.7%, and accuracy was 67.5% and 76.3% for mandibular and medial retropharyngeal lymph nodes respectively. No individual CT findings were predictive of nodal metastasis. Given the low sensitivity of CT, this modality cannot be relied upon alone for assessment of cervical lymph node metastasis in dogs.

A case of benign osteogenic tumour in Homo naledi: Evidence for peripheral osteoma in the U.W. 101-1142 mandible.

The reported incidence of neoplasia in the extinct hominin record is rare. We describe here the first palaeopathological analysis of an osteogenic lesion in the extinct hominin Homo naledi from Dinaledi Cave (Rising Star), South Africa. The lesion presented as an irregular bony growth, found on the right lingual surface of the body of the adult mandible U.W. 101-1142. The growth was macroscopically evaluated and internally imaged using micro-focus x-ray computed tomography (µCT). A detailed description and differential diagnosis were undertaken using gross and micromorphology, and we conclude that the most probable diagnosis is peripheral osteoma - a benign osteogenic neoplasia. These tumours are cryptic in clinical expression, though they may present localised discomfort and swelling. It has been suggested that muscle traction may play a role in the development and expression of these tumours. The impact of this lesion on the individual affected is unknown. This study adds to the growing corpus of palaeopathological data from the South African fossil record, which suggests that the incidence of neoplastic disease in deep prehistory was more prevalent than traditionally accepted. The study also highlights the utility of micro-computed tomography in assisting accurate diagnoses of ancient pathologies.

Amyloid-producing Odontoameloblastoma in a Black-tailed Prairie Dog (Cynomys ludovicianus).

A 6-year-old female black-tailed prairie dog (Cynomys ludovicianus) was presented with a space-occupying lesion in the left submandibular region. On computed tomography, a low attenuating, poorly circumscribed mass infiltrated the left mandibular bone, with osteolytic change. Microscopically, the lesion was composed of odontogenic epithelium proliferating in nests and embedded in abundant dental papilla-like ectomesenchyme, including dentine and enamel. Multifocal amyloid deposition was observed. Immunohistochemically, the neoplastic epithelial cells were positive for cytokeratin (CK) AE1/AE3, CK14 and p63. Some epithelial cells were positive for amelogenin and some adjacent to the amyloid deposits co-expressed S100. The ectomesenchymal cells expressed vimentin and strong S100 immunoreactivity was observed in odontoblast-like cells. The amyloid was immunolabelled with amelogenin. The tumour was diagnosed as amyloid-producing odontoameloblastoma.

Solid type primary intraosseous squamous cell carcinoma in a cat.

BACKGROUND: Squamous cell carcinoma (SCC) is the most common nonodontogenic oral tumor in cats. In the jaw, it usually presents as an ulceroproliferative lesion associated with enlargement of the affected bone. CASE PRESENTATION: This report describes the case of a cat in which clinical and radiographic findings of a mandibular swelling were suggestive of an aggressive process, but the oral mucosa was unaffected. The results of histopathological and immunohistochemical examination of the samples obtained from the intraosseous lesion were consistent with SCC. The animal was euthanized 5 months after initial presentation as a result of the severe progression of the disease, and no other primary tumors were identified at necropsy. CONCLUSIONS: Based on the clinicopathological, microscopic, and immunohistochemical staining features, as well as the absence of a primary tumor at a distant site, we propose that the term, solid type primary intraosseous SCC (PIOSCC), be used to describe this neoplasia, as it shares similar features with human PIOSCC.

Cytologic features of a feline inductive odontogenic tumor.

The feline inductive odontogenic tumor (FIOT) is a rare entity among oral tumors in cats, the cytologic features of which are not well characterized but may prove useful. A fine-needle aspiration biopsy was performed on the right mandible between the permanent canine (404) and permanent fourth premolar (408) of an 8-month-old female mongrel cat. Cytologic smears showed epithelial cells and occasional spindle cells with extracellular homogenous acidophilic material in a hematic background. The initial diagnosis of benign tumor was confirmed by histopathologic examination of the biopsy specimen. This report describes the cytologic findings in a case of FIOT.

Mandibular odontoameloblastoma in a rat and a horse.

Odontoameloblastoma (OA) is a mixed odontogenic tumor that is an ameloblastoma with concurrent histologic evidence of odontoma differentiation. As a mixed tumor, OA is a tripartite lesion comprised of neoplastic odontogenic epithelium, induced dental ectomesenchyme (dental pulp), and mineralized dental matrix. Although rare, OA represents a diagnostic conundrum, as it is histologically closely related to 2 other mixed odontogenic tumors: odontoma (complex and compound) and ameloblastic fibro-odontoma. Herein we describe an OA arising from the mandible of a 4-mo-old Fischer 344 rat that had been exposed in utero to the mutagen ENU (N-ethyl-N-nitrosourea), and a naturally occurring lesion in a 2-y-old Appaloosa horse. In order to satisfy the diagnostic criteria for this lesion, mineralized dental matrix in relationship to neoplastic odontogenic epithelium must be identifiable within the OA lesion. This group of odontogenic tumors is differentiated by the degree to which the dental matrix is organized and the relative proportions of pulp ectomesenchyme, odontogenic matrix, and odontogenic epithelium.

Mandibular Reconstruction by Using a Liquid Nitrogen-Treated Autograft in a Dog with an Oral Tumor.

A 10 yr old intact female German shepherd dog presented with a large peripheral odontogenic fibroma and malignant melanoma on her lower jaw. The tumor was resected with a unilateral subtotal rostral hemimandibulectomy. After the mandible was removed, it was devitalized intraoperatively by freezing it in liquid nitrogen. It was subsequently reimplanted. New bone tissue formed in the gap between the frozen bone and the host bone. The regenerated bone contained osteocytes, osteoblasts, and blood vessels. The cosmetic appearance of the dog was preserved. The dog had normal mastication. The malignant melanoma recurred rostral of the left canine tooth at 159 days after the reconstruction surgery. A subtotal hemimandibulectomy was consequently performed. This is the first reported case of mandibular reconstruction using a liquid nitrogen-treated autograft in a dog with oral tumors.