Outcomes of eight cats with oral neoplasia treated with radical mandibulectomy.

OBJECTIVE: To report outcomes after radical mandibulectomy in cats. STUDY DESIGN: Multi-institutional retrospective study. ANIMALS: Eight cats were included. METHODS: Medical records were searched for cats with confirmed oral neoplasia treated with radical mandibulectomy. Data collected included demographics, surgical procedure, histopathological diagnosis, postoperative management, and outcomes. RESULTS: Ages ranged from 8 to 17 years. All cats had 75% to 90% of the mandible removed and feeding tubes placed. Seven cats had squamous cell carcinoma, and one cat had a giant cell tumor. Six cats ate on their own postoperatively. Three cats had local recurrence and tumor-related died at 136 and 291 days. Six cats had no recurrence, with survival times of 156, 465, 608, and 1023 days, and two cats were still alive at 316 and 461 days after surgery. The three long-term survivors died of causes unrelated to oral neoplasia. One cat died at 156 days due to aspiration of food material. The overall estimated mean survival time was 712 days. CONCLUSION: After radical mandibulectomy, independent food intake was achieved in 6 of eight cats, and four cats lived longer than one year. CLINICAL SIGNIFICANCE: Radical mandibulectomy should be considered for the treatment of extensive oral neoplasia in cats. Successful long-term outcomes are possible with aggressive supportive care perioperatively.

An unusual case of giant cell tumor of soft parts in an American Warmblood horse.

Fine needle aspiration and tissue biopsy samples were taken from a subcutaneous mass in the cranial stifle region of a 10-yr-old horse. Key cytologic features included numerous mildly to moderately pleomorphic histiocytic cells admixed with mononuclear inflammatory cells, occasional fibroblasts, multinucleated cells, and hemosiderin-laden macrophages. Based on these features, cytologic differentials included granulomatous inflammation with reactive fibroplasia, histiocytic sarcoma, giant cell tumor of soft parts (GCTSPs), and giant cell tumor of bone. The tissue biopsy supported a diagnosis of superficial GCTSPs. This neoplasm is of controversial origin but generally considered to be a soft tissue sarcoma and classified in the World Health Organization classification of tumors under fibrous histiocytic tumors as a giant cell tumor of soft tissue with low risk of malignancy. When found in the subcutis, this neoplasm rarely metastasizes in the horse and has a low rate of local reoccurrence. In this case, there was no local recurrence of the tumor after 6 mo, after which the horse was lost to follow-up.

A case of giant cell tumor of soft parts in a horse.

A 12-year-old British Warmblood mare was examined by the referring veterinarian for evaluation of a cutaneous lesion on the dorsal thorax to the right of the midline. Cytologic examination of fine-needle aspirates from the mass was supportive of a giant cell tumor of soft parts (GCTSP). Laser surgical excision and postoperative methyl aminolevulinate (MAL) photodynamic therapy (PDT) were performed. Histologic examination of the mass confirmed the cytologic diagnosis. At 8 months from surgery, no evidence of recurrence has been observed. Giant cell tumors of soft parts are rare cutaneous neoplasms, observed in several domestic species, including the horse where they commonly appear as superficial cutaneous lesions without aggressive biologic behavior. Previously classified as giant cell variant of malignant fibrous histiocytoma, these superficial tumors have now been designated as giant cell tumors of soft tissue or giant cell tumors of low malignant potential within the category of fibrohistiocytic neoplasms.

IMAGING DIAGNOSIS-THE COMPUTED TOMOGRAPHIC APPEARANCE OF A GIANT CELL TUMOR AFFECTING THE MANDIBLE IN A PYGMY GOAT.

A 3-year-old male neutered pygmy goat presented for evaluation of a progressive mandibular swelling and inappetence. A computed tomographic (CT) scan of the head and thorax was performed under general anesthesia. Computed tomography revealed an extensive multiloculated, markedly expansile lesion within the right hemimandible, which involved the articular surface of the temporomandibular joint. The goat was euthanased due to a poor prognosis and postmortem examination confirmed the diagnostic imaging findings. Histopathology was strongly suggestive of a multinucleated giant cell tumor, therefore this condition should be considered as a differential diagnosis in goats presenting with expansile mandibular mass lesions.

Cytologic findings from a benign giant cell tumor of the tendon sheath in a dog.

A 6-year-old male neutered Australian Shepherd dog was presented for evaluation of a subcutaneous mass on the plantar aspect of the proximal left metatarsus. Fine-needle aspirate smears contained numerous plump spindle cells and large multinucleated cells amongst a considerable amount of pink extracellular matrix. Histopathologic diagnosis of the tissue obtained during initial biopsy and eventual surgical cytoreduction of the mass was a benign giant cell tumor of the tendon sheath (GCTTS). Immunohistochemically, the synovioblastic neoplastic cells were diffusely strongly positive for vimentin and S-100, were multifocally moderately positive for cytokeratin AE1/3, and were negative for CD18, muscle-specific actin (MSA), and melanoma-associated antigen (mutated) 1 (MUM-1). The dog recovered from surgery and underwent definitive radiation therapy to treat the local residual disease. Eight months later, the mass had not recurred. The diagnosis of GCTTS in this case supports previously published reports describing GCTTS as a relevant disease entity in dogs, and provides the first documentation of cytologic findings with this tumor. Further investigation is needed to correlate pathologic features with clinical behavior and response to therapy in dogs.

Equine giant cell tumor of soft parts: a series of 21 cases (2000-2007).

In horses, giant-cell tumors of soft parts are rare neoplasms, with the majority of reported cases occurring within the hind limb muscles and soft tissues in older horses. The following article documents 21 cases of equine giant-cell tumors of soft parts clinically examined within the state of Colorado from 2000 to 2007. The majority of cases occurred in male horses aged 10 years or older. Nine (43%) arose within the hind limbs. Key histologic features included numerous multinucleated giant cells and hemosiderin-laden macrophages admixed with a spindle-cell proliferation. The majority demonstrated liposarcomatous change, variable areas of necrosis and hemorrhage, and an intermediate number of mitotic figures. Immunohistochemical results demonstrated 2 distinct cell populations: vimentin-expressing neoplastic mesenchymal cells and CD18 (histiocytic marker) expressing multinucleated giant cells. These results suggest a mesenchymal origin of the neoplasm with possible recruitment of the secondary histiocytic population. Surgical excision was attempted in the majority of horses and was considered clinically complete. A recurrence of the neoplasm was documented in 1 horse and 1 mule. In 18 horses, surgical excision, regardless of margin integrity, appeared successful with no recurrence of disease documented. Unfortunately, 10 of 21 horses were lost to follow-up within approximately 3 months of surgery. Of the 11 remaining horses that were available for follow-up evaluation, there has been no evidence of metastasis. A larger case series with more controlled follow-up is necessary to evaluate malignant potential and the importance of complete surgical excision.

Osteoclastic-like giant cell tumour in a cat.

An 11-year-old neutered male domestic shorthair cat was presented with an epulis. A hemispherical mass, 8mm in maximum diameter, without a peduncle and bright reddish in colour, was observed on the gingiva of the left mandible. Radiography failed to show any infiltrating osteolysis. The epulis was surgically removed via gingival incision around the margin to the depth of connective tissue layer. Histopathological examination indicated that the epulis contained a large number of multinucleated giant cells (MGCs) intermixed with mononuclear mesenchymal cells in a loose fibrovascular stroma. Mitotic cells were found, mainly in the centre of the mass. MGCs were stained positive by the tartrase resistant acid phosphatase (TRAP) staining, indicating osteoclasts activity. Immunohistochemical staining for proliferating-cell nuclear antigen (PCNA) was observed within the majority of mononucleated cells, whereas multinucleated cells did not stain. An osteoclast-like giant cell tumour was concluded in this case. The origin of epulis is likely from the periosteal tissue. The cat recovered uneventfully and no recurrence has been noted for 3 years thereafter.

Osteoclast-like giant cell tumour arising from the kidney in a dog.

In this study, a case of osteoclast-like giant cell tumour arising from the kidney is reported in an eight-year-old female Anatolian Shepherd dog. Macroscopically, the tumorous mass covered the hilus of the left kidney. It was 26 x 22 x 12 cm in size and 3700 g in weight. Metastatic tumorous nodules, 0.5-2.0 cm in diameter, were found on the abdominal side of the diaphragm and in the lungs. Microscopically, numerous large osteoclast-like multinucleated giant cells and spindle-spheroidal-shaped cells were seen. Osteoblastic differentiation and osteoid matrix were noted in a few areas at the periphery of the tumour, near the connective tissue septa. The stroma of the tumour tissue was vascular, oedematous and loose. By immunoperoxidase staining, tumour cells showed immunoreactivity for vimentin but not for keratin and desmin, indicating that the tumour had mesenchymal origin. This is the first report in the literature on a malignant osteoclast-like giant cell tumour arising from a visceral organ in animals.

Benign giant cell tumour of tendon sheaths in a European Lynx (Lynx lynx).

The histological, histochemical, immunohistochemical and ultrastructural features of a benign giant cell tumour (BGCT) of tendon sheaths in a 12-year-old male European lynx (Lynx lynx) are reported herein. The neoplastic mass involved the subcutaneous and inter-muscular tissues of the first, second, third and fourth digit of the left forelimb, from the phalanxes up to the carpus. The tumour appeared as a grey-whitish tissue mottled with darker areas, along with several scattered foci of orange colour. Histologically, the lesion consisted of a mixed population of numerous, multinucleated giant cells and epithelioid or spindle-shaped mononuclear cells embedded in a loose, highly vascular stroma. Neoplastic cells lined cleft formations and synovial-like projections into cystic spaces. No osteoid matrix could be detected. Haemorrhage and necrosis were also observed. The mononuclear and the giant cells were tartrate-resistant acid phosphatase and periodic acid-Schiff positive, being also immunohistochemically reactive for lysozyme and vimentin, with a few cells showing immunopositivity also for alpha-1-antitrypsin. Ultrastructurally, histiocyte-like cells, fibroblast-like cells and multinucleated giant cells were observed, but no virus-like particles could be detected in any of the above cell types. The BGCT of tendon sheaths, a fairly uncommon neoplasm in animals, has not been previously reported in the lynx.

Malignant giant cell tumor of soft parts in a mare.

Two subcutaneous masses were removed from the elbow of a mare. Histologically they were composed of islands of polygonal to plump spindlelioid cells with large nuclei, coarsely stippled chromatin, and eosinophilic cytoplasm. Findings were diagnostic for a malignant giant cell tumor of soft parts, a rare tumor with a fair prognosis.

Giant cell tumor of the accessory carpal bone in a dog.

A 4-year-old Springer Spaniel was referred because of a 6-week history of progressive left forelimb lameness. A marked pain response was elicited by palpation over the left accessory carpal bone. Radiography revealed a lytic, markedly expansile lesion of the accessory carpal bone. The bone was excised, and pancarpal arthrodesis was performed. Histologic examination of the excised bone revealed giant cell tumor. At 14 months after surgery, the dog was using the limb normally. Radiography of the carpus revealed satisfactory progression of the arthrodesis, and thoracic radiographs were negative for metastases.

Equine giant cell tumor of soft tissues.

During a routine necropsy examination of a 4-year-old standardbred mare, a well-demarcated dermal mass was seen near the right elbow. Grossly, the mass consisted of multifocal variably sized areas of dark brown, firm material that was separated by thin white septa. Histologically, within the individual compartments, there were numerous multinucleated giant cells, macrophages, and free erythrocytes. A diagnosis of giant cell tumor of soft tissues was made.

Giant-cell tumour of soft tissue in two Sprague-Dawley rats.

Two cases of soft tissue giant-cell tumours are reported in Sprague-Dawley rats. The lesions had the characteristic appearance of multinucleate tumour giant cells and were unassociated with bone. A search of the literature failed to reveal any previous report of this lesion in the rat.

Giant cell tumor of soft parts in six horses.

Giant cell tumor of soft parts was diagnosed in 6 horses 3 to 12 years old (mean, 6.8 +/- 3.5 years): 3 Quarter Horse geldings, 2 Standardbred mares, and 1 Standardbred stallion. The neoplasms developed as raised, solitary masses, approximately 1 to 4 cm in diameter, which were firmly attached to subcutaneous tissue of the neck (1 horse), shoulder (1 horse), thigh (2 horses), or stifle (2 horses). Excision was followed by local recurrence in 3 horses within 1 to 1 1/2 months. The neoplasms were firm and cut with resistance. On cut surface, they were white, with mottled red hemorrhagic areas.

Feline malignant giant cell tumor of bone associated with C-type virus particles.

A malignant giant cell tumor of bone in a cat is described. Numerous C-type particles were found budding from the neoplastic cells. Viruses have not previously been associated with malignant bone noeplasms in cats.

Comparative pathology of bone tumors in animals, with particular emphasis on the dog.

A review of bone tumors in animals, based on cases reported in the literature and on personal examination of cases from several universities in the U.S.A. and Europe, has shown that: 1. The following bone tumors occur in decreasing order of frequency in animals: osteosarcoma, chondrosarcoma, osteochondroma, hemangiosarcoma, fibrosarcoma, and liposarcoma; 2. The dog has by far the highest frequency of bone tumors; and osteosarcomas account for approximately 80 percent of bone tumors in dog, followed by chondrosarcomas and hemangiosarcomas; 3. Bone tumors occur less frequently in the cat than in the dog, and are of essentially the same types and incidence as in the dog; 4. Sheep has a unique propensity for chondrosarcoma and primary bone tumors are rare in other species; 5. Giant cell tumors, reticulum cell sarcomas, and Ewing's sarcomas are exceptional findings in animals.