Sternal osteosarcoma in a blue crane (Anthropoides paradiseus)

Osteosarcoma of the wing in a sulfur-crested cockatoo

A 26-year-old female sulfur-crested cockatoo (Cacatua galerita) was evaluated for vocalizing through the night and extending her right wing. Physical examination revealed a large, firm mass extending from the humerus to the distal aspect of the elbow. Computed tomography confirmed a large aggressive mass of the right distal humerus with a large soft tissue component, severe osteolysis, and adjacent periosteal proliferation. Fine-needle aspirates of the mass were most compatible with sarcoma, and osteosarcoma was prioritized. An unstained slide was treated with nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate toluidine salt-phosphatase (NBT/BCIP) substrate for ALP detection and was strongly positive, confirming a diagnosis of osteosarcoma. A month later, the patient underwent wing amputation and arrested during recovery from anesthesia. Post-mortem examination and histopathology were consistent with osteosarcoma. This case report highlights a rare occurrence of osteosarcoma in a cockatoo as well as its cytologic and histologic features. Additionally, this report provides support for NBT/BCIP application in ALP-expressing tumors, a cytochemical stain that has been minimally investigated in avian species.

Telangiectatic Osteosarcoma of the Tibiotarsus in a North Island Brown Kiwi (Apteryx mantelli)

A North Island brown kiwi (Apteryx mantelli) with lameness and weight loss had a telangiectatic osteosarcoma. The left proximal tibiotarsus had bony lysis with multiple blood-filled spaces separated by thick fibrous septa and neoplastic mesenchymal cells producing osteoid (5-bromo-4-chloro-3'-indolyl phosphate/nitro blue tetrazolium positive on cytology). No metastases were noted on necropsy.

NEOPLASIA IN CAPTIVE CRANES

A retrospective study of neoplasia was conducted from necropsy and histologic reports of 446 cranes representing all 15 extant species. Cases were obtained from the International Crane Foundation (ICF), Northwest ZooPath (NWZP), and six other zoologic institutions in the United States during 1993 to 2019. Only reports from ICF (n = 61) and NWZP (n = 374) were used for estimates of disease prevalence. Overall prevalence of neoplasia was 7.35% (32 of 435), with a metastasis rate of 31.8%. Seventeen types of neoplasms were identified. Geriatric cranes were the most common age class affected (60%). The digestive system was most frequently involved (n = 12; 27.3%), followed by urinary (n = 8; 18.2%) and integumentary systems (n = 6; 13.6%). Carcinoma was the most common tumor type across all species (n = 15; 34.0%) followed by benign epithelial tumors (adenomas; n = 11; 25.0%). Multiple neoplasms were observed in only one crane. Of the cases with metastasis, hematopoietic, reproductive, and respiratory tumors had 100% metastasis (2 of 2, 2 of 2, and 3 of 3, respectively), whereas tumors of the integumentary, nervous, and musculoskeletal systems had no evidence of metastasis (0 of 7, 0 of 3, and 0 of 1, respectively). Overall, Gruidae species were found to have a high prevalence of neoplasia but a low rate of metastasis compared with other avian species with the highest species-specific rates in Eurasian (Grus grus), demoiselle (Anthropoides virgo), and wattled cranes (Bugeranus carunculatus) (40.0%, 21.4%, and 19.0%, respectively). This is the first large-scale study of neoplasia in cranes.

Polyostotic osteosarcoma associated with avian leukosis virus infection in a captive bare-faced curassow (Crax fasciolata)

Background

Osteosarcoma is a malignant mesenchymal bone tumor. Although it is a common tumor in the appendicular skeleton of dogs and cats, it is rarely reported in birds. Retroviruses are usually associated with solid tumor development in different avian species.

Case presentation:

This report aims to describe a case of osteosarcoma associated with the avian leukosis virus in a captive bare-faced curassow (Crax fasciolata). A captive adult female bare-faced curassow presented with lameness, hyporexia, and a non-ulcerative and firm tumor in the right femur. The bird was euthanized due to the poor prognosis. Histopathology revealed an infiltrative mesenchymal neoplasm consisting of spindle cells with moderate cell pleomorphism, organized in bundles and interspersed by marked deposition of the osteoid matrix, which was compatible with osteosarcoma affecting both femur and tibiotarsus, with renal metastasis. Immunohistochemistry of the primary and metastatic tumor demonstrated vimentin expression by neoplastic cells. Samples of the neoplasm, bone marrow, and spleen were processed for PCR, which enabled the demonstration of proviral avian leukosis virus (ALV) DNA.

Conclusions

To the best of our knowledge, this is the first report of an osteosarcoma in a bare-faced curassow with an unusual polyostotic manifestation and associated with ALV infection.

Risk Factors for Development of Canine and Human Osteosarcoma: A Comparative Review

Osteosarcoma is the most common primary tumor of bone. Osteosarcomas are rare in humans, but occur more commonly in dogs. A comparative approach to studying osteosarcoma has highlighted many clinical and biologic aspects of the disease that are similar between dogs and humans; however, important species-specific differences are becoming increasingly recognized. In this review, we describe risk factors for the development of osteosarcoma in dogs and humans, including height and body size, genetics, and conditions that increase turnover of bone-forming cells, underscoring the concept that stochastic mutational events associated with cellular replication are likely to be the major molecular drivers of this disease. We also discuss adaptive, cancer-protective traits that have evolved in large, long-lived mammals, and how increasing size and longevity in the absence of natural selection can account for the elevated bone cancer risk in modern domestic dogs.

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.