Observations on naturally occurring neoplasms in birds in the state of Victoria, Australia

Life history traits and cancer prevalence in birds

Background and objectives

Cancer is a disease that affects nearly all multicellular life, including the broad and diverse taxa of Aves. While little is known about the factors that contribute to cancer risk across Aves, life history trade-offs may explain some of this variability in cancer prevalence. We predict birds with high investment in reproduction may have a higher likelihood of developing cancer. In this study, we tested whether life history traits are associated with cancer prevalence in 108 species of birds.

Methodology

We obtained life history data from published databases and cancer data from 5,729 necropsies from 108 species of birds across 24 taxonomic orders from 25 different zoological facilities. We performed phylogenetically controlled regression analyses between adult body mass, lifespan, incubation length, clutch size, sexually dimorphic traits, and both neoplasia and malignancy prevalence. We also compared the neoplasia and malignancy prevalence of female and male birds.

Results

Providing support for a life history trade-off between somatic maintenance and reproduction, we found a positive relationship between clutch size and cancer prevalence across Aves. There was no significant association with body mass, lifespan, incubation length, sexual dimorphism, and cancer.

Conclusions and implications

Life history theory presents an important framework for understanding differences in cancer defenses across various species. These results suggest a trade-off between reproduction and somatic maintenance, where Aves with small clutch sizes get less cancer.

Lymphomas in seabirds: case reports in a black skimmer (Rynchops niger) and a brown booby (Sula leucogaster)

A black skimmer (Rynchops niger) and a brown booby (Sula leucogaster) were rescued and gross, histopathological, immunohistochemical and polymerase chain reaction evaluations were conducted to investigate the cause of death. There were neoplastic infiltrations of CD3+ PAX5- lymphocytes in the black skimmer and CD3- PAX5+ lymphocytes in the brown booby. Molecular assays for viral agents were negative in both cases. This is the first report of disseminated lymphoma as the cause of stranding and death in these species in Brazil.

Pathological findings and their association with diseases of captive psittacine birds native to Mexico

The captivity and use of native psittacine birds is prohibited in Mexico. However, as these birds are among the groups most affected by illegal trafficking, they are commonly found as companion animals. Nevertheless, it is difficult to obtain information on their health. Therefore, a retrospective study was conducted of the clinical histories and necropsy reports of native psittacines that had been submitted to the Bird Disease Diagnostic and Research Laboratory of the Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, from 2006 to 2017. The lesions were classified according to type and anatomical location and the diseases were classified as infectious or non-infectious. During this period, 252 psittacines were submitted, the most frequent of which were the red-lored parrot (Amazona autumnalis), orange-fronted parakeet (Eupsittula canicularis) and scarlet macaw (Ara macao). The lesions were primarily located in the digestive and respiratory systems. By integrating the clinical histories and post-mortem findings, we concluded that nutritional disorders were the most frequent non-infectious diseases, systemic bacterial infections were the most frequent infectious conditions, the primary parasite was Sarcocystis spp and the most frequent neoplasm was multicentric lymphoma.

Macroscopic, cytological and histological diagnosis of proventricular adenocarcinoma in a sulphur-crested cockatoo (Cacatua galerita)

An adult sulphur-crested cockatoo (Cacatua galerita) was unexpectedly found dead and was presented for post-mortem examination. Macroscopically, the proventricular wall was expanded by an infiltrative off-white mass, 10 mm in diameter, with secondary mucosal ulceration. Cytological examination of impression smears revealed a neoplastic epithelial cell population forming occasional well-defined acini with secretory product. Histologically, the neoplastic cells were predominantly arranged in acini and tubules, with fewer in small clusters, supported by a desmoplastic stroma. Neoplastic cells were polygonal, with mostly well-demarcated cell boundaries and a moderate amount of eosinophilic cytoplasm that was multifocally markedly distended by more intensely eosinophilic material. There was an increased nuclear-to-cytoplasmic ratio with moderately sized to large nuclei (approximately 15 μm diameter) with lightly to densely stippled chromatin and single or paired prominent basophilic nucleoli. The mitotic count was 19 in 10 high-power fields (2.37 mm2), with scattered bizarre mitotic figures and atypia including moderate anisocytosis and anisokaryosis and moderate cellular and nuclear pleomorphism. There was frequent intratubular brightly eosinophilic proteinaceous material, which was Alcian blue and periodic acid‒Schiff positive. Proventricular lymphovascular invasion was detected, with metastases within the ventriculus and lungs. The macroscopic, cytological and histological appearance of the neoplasm was consistent with a proventricular adenocarcinoma.

Survey of the Clinical, Cytological, and Histopathological Features Associated with Neoplasms in Captive Avian Species in Melbourne, Australia

Over a 3.5-year period, tissue samples from 141 companion and aviary birds with clinically suspected, naturally occurring solid neoplasms were collected via surgical biopsy (n = 53) or at necropsy examination (n = 88) from a population of birds presenting to an avian veterinary clinic in Melbourne, Australia. Neoplastic processes were identified in 73.7% (n = 104) of samples, with 83.7% (n = 87) being interpreted as malignant neoplasia and 16.3% (n = 17) being interpreted as benign neoplasia. The overall estimated prevalence of neoplasia in the study population (n = 5125) was 2.45% (95% confidence interval, 2-2.97%). The gastrointestinal and reproductive tracts were the most commonly affected systems. The most common presenting signs were nonspecific and included lethargy, coelomic distension, and inappetence. In 59 cases, fine-needle aspirates (FNAs) and impression smears were also obtained and evaluated cytologically. The accuracy of cytology for detecting neoplasia in birds and for determining whether a neoplastic process was benign or malignant was assessed by using histopathology as the "gold standard." There was complete agreement between the cytological and histopathological diagnoses in 72.8% (43/59) of cases. Cytology correctly identified 87.5% of these cases (35/40) as malignant neoplasms and 55.6% (5/9) as benign processes. There was no significant difference between the use of cytology and histopathology for the detection of malignant neoplasia in birds (P = 0.185). The accuracies of FNAs and impression smears for examining avian tumors were also compared. Overall, the best cell preservation was obtained by performing impression smears from tissues, with 62.2% (n = 28) returning high cellularity for cytological examination, compared to 53.8% (n = 14) when samples were obtained by FNA. This study provides an overview of the types and prevalence of neoplasms in a captive bird population from Australia, correlates physical examination findings with tumor types, and provides evidence that cytology is a reliable preliminary diagnostic tool for detecting neoplasia in birds.

Life history and cancer in birds: clutch size predicts cancer

Cancer is a disease that affects nearly all multicellular life, including birds. However, little is known about what factors explain the variance in cancer prevalence among species. Litter size is positively correlated with cancer prevalence in managed species of mammals, and larger body size, but not incubation or nestling period, is linked to tumor prevalence in wild birds. Also, birds that produce more elaborate sexual traits are expected to have fewer resources for cancer defenses and thus higher cancer prevalence. In this study, we examined whether cancer prevalence is associated with a wide variety of life history traits (clutch size, incubation length, body mass, lifespan, and the extent of sexual dimorphism) across 108 species of managed birds in 25 different zoological facilities, sanctuaries, and veterinary clinics. We found that clutch size was positively correlated with cancer and neoplasia (both benign and malignant) prevalence, even after controlling for body mass. Cancer prevalence was not associated with incubation length, body mass, lifespan, or sexual dimorphism. The positive correlations of clutch size with cancer prevalence and neoplasia prevalence suggest that there may be life-history trade-offs between reproductive investment and somatic maintenance (in the form of cancer prevention mechanisms) in managed birds.

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.

Medullary bone in male budgerigars (Melopsittacus undulatus) with testicular neoplasms

Medullary bone is a calcium-rich, labile bone normally occurring in female birds with each egg-laying cycle. The stimulus for formation of medullary bone is, in part, the cyclic increase in serum estrogens produced by preovulatory ovarian follicles. Increased bone density due to formation of medullary bone, particularly in pneumatic bones, has been termed polyostotic hyperostosis, even if physiologic. This study investigated the formation of medullary bone in nonpneumatic (femur) and pneumatic (humerus) bones in sexually mature male budgerigars submitted for autopsy. Of the 21 sexually mature male budgerigars submitted for autopsy, 7 (33%) had medullary bone in 1 or more bones examined. All 7 male budgerigars with medullary bone had a testicular neoplasm, which was morphologically consistent with a testicular sustentacular cell tumor, seminoma, or interstitial cell tumor. Medullary bone was not present in the 14 cases with other diseases. Medullary bone formation in pneumatic and nonpneumatic bones can occur in male budgerigars with testicular neoplasms. Radiographic increases in medullary bone density, particularly in the humerus, could provide antemortem indication of testicular neoplasia in male budgerigars.

Uveal Malignant Melanoma in a Hybrid Macaw Parrot (Ara chloropterus × Ara militaris)

An adult male green-winged (Ara chloropterus) × military (Ara militaris) hybrid macaw of unknown age was presented to the Texas A&M Veterinary Medical Teaching Hospital for evaluation of left periocular swelling, blepharospasm, and ocular discharge. Complete ophthalmic examination and B mode ocular ultrasonography were performed to evaluate the affected eye. Ocular examination revealed a blind left globe with exophthalmos, periocular swelling, diffuse corneal edema, and severe anterior fibrinous uveitis obscuring visualization of the intraocular structures. An ultrasound examination revealed a hyperechoic mass that filled the posterior segment of the globe. Focal discontinuity of the posterior sclera suggested scleral rupture. Enucleation with histopathology was recommended and performed 1.5 months later. Intraoperatively, a heavily pigmented and friable soft tissue mass extruded through the posterior sclera and extended into the orbit. Histologically, the mass was consistent with a malignant melanoma. The patient died 18 hours after the surgical procedure because of unknown complications. Postmortem examination did not identify evidence of metastasis. This study described the clinical appearance and histopathologic findings of a rare ocular neoplasm with extrascleral extension in a hybrid macaw. Although uncommon in psittacine birds, primary ocular melanocytic neoplasms may display features of malignancy with scleral or orbital invasion, or both.

Intestinal-peritoneal Coelioscopy for the Diagnosis of a Mesothelioma in a Pet Chicken

An adult female chicken, from a small backyard flock, was presented to the Ontario Veterinary College Avian and Exotics Service for evaluation of dyspnea and recurrent ascites. An antemortem diagnostic evaluation included a coelomocentesis, coelomic ultrasound, and a coelioscopy procedure. A sample of the fluid collected during the coelomocentesis was submitted for analysis and was determined to be a nonspecific modified proteinaceous transudate. The coelomic ultrasound examination identified numerous coalescing fluid-filled and solid nodules throughout the coelom. However, no site of origin of the nodules could be identified. A coelioscopy of the intestinal-peritoneal cavity was performed by a ventral midline approach, and biopsies collected during the procedure were submitted for histologic examination. The pathologic diagnosis of the biopsy samples was a disseminated neoplasia, presumptively coelomic adenocarcinoma. The chicken received palliative treatment which included periodic coelomocentesis, meloxicam, antibiotics, and deslorelin following the diagnosis of a disseminated neoplasia. Three months following initial presentation the patient was euthanatized. A postmortem examination with histopathology confirmed the tissue biopsy results of coelomic neoplasia. Further immunohistochemistry supported mesothelioma as the definitive diagnosis. This case documents the usefulness of intestinal-peritoneal coelioscopy in identifying neoplasia as the cause of ascites in a pet chicken as well as describing the clinical features and progression of a mesothelioma in this species.

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.

Case Report: Multiple Cavernous Pericardial Lymphangioma (Pericardial Lymphangiomatosis) in a Captive Peregrine Falcon (Falco peregrinus brookei)

A 12-year-old female peregrine falcon (Falco peregrinus brookei) from a private raptor breeding facility that presented a good body condition, died suddenly without showing previous symptoms. At necropsy, in the coelomic cavity, multiple cystic structures demarcated by a thin transparent wall and filled with a serous content were observed. They were firmly adhered to the cranial part of the epicardium and adjacent tissues and occupied the entire thoracic area of the coelomic cavity. Microscopically, emerging simultaneously from several areas the epicardium, multiple irregular channels and cystic spaces, lined by a single endothelial cell layer and separated by fibrovascular septa containing smooth muscle tissue, were observed. Immunohistochemical examination revealed that the neoplastic endothelial cells positively immunolabelled for the pan-endothelial marker factor VIII-related antigen but immunostained negative for cytokeratins (PCK26) while strong positivity for sarcomeric α-smooth muscle actin (α-SMA) was detected in the cystic walls. Based on the morphological and immunohistochemical findings, lesions were determined as consistent with a multiple cavernous pericardial lymphangioma, or pericardial lymphangiomatosis, a rare vascular neoplasm. The animal also showed a diffuse chronic perihepatitis, a necrotic area in the liver and foci of cartilaginous metaplasia and calcification in the aorta and vena cava. Literature review, particularly on the epidemiology of lymphangioma, demonstrated the rarity of this tumor in the different animal species and in this location, particularly in birds, being the first report of this type of tumor in a peregrine falcon.

Cutaneous leiomyosarcoma with visceral metastases in a White Carneau pigeon and literature review

Cutaneous leiomyosarcomas are malignant mesenchymal tumors of smooth muscle origin and are reported occasionally in avian species. A 14-y-old male laboratory White Carneau pigeon (Columba livia) was presented for surgical excision of a cervical soft tissue mass. Ultrasonography with color flow Doppler imaging revealed multiple cavitations of mixed echogenicity within the mass and vascularization. Histologically, the dermis and subcutis were expanded by a densely cellular multinodular mass comprised of fusiform cells forming haphazardly arranged broad streams and short interwoven bundles, often surrounding blood vessels and variably sized cavitations. Neoplastic cells were strongly immunopositive for desmin and α-smooth muscle actin, and negative for pancytokeratin, S100, and von Willebrand factor. Based on histopathology and IHC findings, the cutaneous mass was diagnosed as leiomyosarcoma (LMS). The pigeon died 312 d post-operatively. Postmortem examination revealed masses infiltrating the left and right pulmonary airways and one hepatic nodule, but no regrowth at the surgical site. Histologic and IHC evaluation of the pulmonary and hepatic masses were consistent with LMS, representing metastatic foci from the primary cutaneous LMS. Our case highlights the malignant behavior and histomorphologic features of cutaneous LMS in an avian species.

A comprehensive diagnostic approach combining phylogenetic disease bracketing and CT imaging reveals osteomyelitis in a Tyrannosaurus rex

Traditional palaeontological techniques of disease characterisation are limited to the analysis of osseous fossils, requiring several lines of evidence to support diagnoses. This study presents a novel stepwise concept for comprehensive diagnosis of pathologies in fossils by computed tomography imaging for morphological assessment combined with likelihood estimation based on systematic phylogenetic disease bracketing. This approach was applied to characterise pathologies of the left fibula and fused caudal vertebrae of the non-avian dinosaur Tyrannosaurus rex. Initial morphological assessment narrowed the differential diagnosis to neoplasia or infection. Subsequent data review from phylogenetically closely related species at the clade level revealed neoplasia rates as low as 3.1% and 1.8%, while infectious-disease rates were 32.0% and 53.9% in extant dinosaurs (birds) and non-avian reptiles, respectively. Furthermore, the survey of literature revealed that within the phylogenetic disease bracket the oldest case of bone infection (osteomyelitis) was identified in the mandible of a 275-million-year-old captorhinid eureptile Labidosaurus. These findings demonstrate low probability of a neoplastic aetiology of the examined pathologies in the Tyrannosaurus rex and in turn, suggest that they correspond to multiple foci of osteomyelitis.

Age-dependent expression of cancer-related genes in a long-lived seabird

Studies of model animals like mice and rats have led to great advances in our understanding of the process of tumorigenesis, but this line of study has less to offer for understanding the mechanisms of cancer resistance. Increasing the diversity of nonmodel species from the perspective of molecular mechanisms of natural cancer resistance can lead to new insights into the evolution of protective mechanisms against neoplastic processes and to a wider understanding of natural cancer defense mechanisms. Such knowledge could then eventually be harnessed for the development of human cancer therapies. We suggest here that seabirds are promising, albeit currently completely ignored candidates for studying cancer defense mechanisms, as they have a longer maximum life span than expected from their body size and rates of energy metabolism and may have thus evolved mechanisms to limit neoplasia progression, especially at older ages. We here apply a novel, intraspecific approach of comparing old and young seabirds for improving our understanding of aging and neoplastic processes in natural settings. We used the long-lived common gulls (Larus canus) for studying the age-related pattern of expression of cancer-related genes, based on transcriptome analysis and databases of orthologues of human cancer genes. The analysis of differently expressed cancer-related genes between young and old gulls indicated that similarly to humans, age is potentially affecting cancer risk in this species. Out of eleven differentially expressed cancer-related genes between the groups, three were likely artifactually linked to cancer. The remaining eight were downregulated in old gulls compared to young ones. The downregulation of five of them could be interpreted as a mechanism suppressing neoplasia risk and three as increasing the risk. Based on these results, we suggest that old gulls differ from young ones both from the aspect of cancer susceptibility and tumor suppression at the genetic level.

Bilateral osteoma cutis in a Peach-Faced Lovebird (Agapornis roseicollis)

An osteoma is an infrequent tumor documented in avian species. An adult female Peach-Faced Lovebird (Agapornis roseicollis) with a history of previous trauma was examined due to the presence of bilateral hard and yellowish-white masses in the radio-cubital humerus junction. Histopathological dermal examination revealed a non-neoplastic process of mesenchymal origin, characterized by the formation of well-differentiated trabecular bone, multiple areas of medullary bone and loose connective tissue and coagulation of the necrosis foci. Based on the histological findings and the medical history, the masses were diagnosed as bilateral secondary osteoma cutis. To our knowledge, this is the first report of this pathology with an acute course in this exotic pet bird. The previous trauma could be the initiating cause.

Multicystic peritoneal tumor in two layer hens

In chicken, peritoneal cystic lesions have not been clearly categorized. In this study, diffuse peritoneal multiple cysts were observed in two layer hens. The cysts in the serosa were lined with single layers of squamous or cuboidal cells. The papillary proliferations of columnar cells were also observed in one case. The smooth muscle layer or mass were observed around the cysts in both cases. The cystic lining cells were positive for pan-cytokeratin, vimentin, S100 and Wilms tumor 1. Ultrastructurally, they had sparsely microvilli on the luminal surface. The histological results indicated the present cases were multicystic mesothelioma, but also had characteristics of Mullerian epithelium. This is the first report describing the detailed pathological feature of unique multicystic tumor in chicken.

Liposarcoma in a Backyard Silkie and Retrospective Summary of Neoplasms Diagnosed in Backyard Chickens Submitted to the California Animal Health and Food Safety Laboratory System, 2008-2017

Liposarcomas are a malignant neoplasm of adipocytes, and are rarely diagnosed in avian species. This case report describes the evidence supporting a diagnosis of metastatic liposarcoma in a backyard silkie chicken. On September 28, 2017, a dead 3-yr-old backyard silkie chicken, with a history of unknown skin lesions involving the entire body and severe weight loss, was submitted to California Animal Health and Food Safety Laboratory System-Turlock branch for necropsy. At necropsy, raised necrotic lesions involving the majority of the skin and multiple nodules in the liver, spleen, and bone marrow were noticed. Microscopically, stellate, spindle, and myxoid cells containing large vacuoles, which were confirmed as lipid droplets by Oil Red O, were observed infiltrating the dermis and underlying a necrotic epidermis, with metastasis to liver, spleen, bone marrow, and ovary being the most significant findings. PAS, Oil Red O, Ziehl-Neelsen, Congo red, Gram, and Von Kossa stains, along with immunohistochemistry for pan cytokeratin, vimentin, S100, CD3, pp38, and Meq were used to classify the lesions. Intensely positive vimentin immunohistochemistry, along with large quantities of Oil Red O-positive lipid droplets within the neoplastic cells, were supportive of our diagnosis of liposarcoma. The incidence of neoplastic diseases diagnosed in backyard flock submissions to CAHFS system wide from 2008 to 2017 was also reviewed.

Electrochemotherapy for the treatment of an incompletely excised subcutaneous low-grade epithelioid hemangioendothelioma in a budgerigar parakeet (Melopsittacus undulatus)

Background

Cutaneous tumors are rarely described in avian and are frequently of viral origin. Solid tumors of vascular origin are seldom reported and usually result in difficult management by surgery alone. We describe the outcome of a subcutaneous low-grade epithelioid hemangioendothelioma (EHE) treated with the combination of surgery and electrochemotherapy.

Case Description

A 10-year-old male budgerigar parakeet (Melopsittacus undulatus) was referred for evaluation of a 2-month non-healing exophytic mass on the left wing. The bird was bright, alert, and responsive, with a 2 × 1 cm proliferative lesion on the wing. Signs of discomfort were elicited by the clinical manipulation of the wing; no other abnormalities were detected during physical evaluation. Following hematological and imaging analysis, the parakeet was anesthetized and the mass was surgically removed. The histopathology report came back with a diagnosis of incompletely excised subcutaneous low-grade EHE. A surgical revision was not feasible due to the anatomical location and tumor extension. Adjuvant electrochemotherapy was chosen to increase the chance of tumor control. Two sessions of electrochemotherapy were performed with a 2-week interval between treatments using intralesional bleomycin followed by trains of permeabilizing electric pulses. Side effects were not observed and the parakeet was disease-free for 12 months when he died of acute renal failure.

Conclusion

In lieu of the incomplete surgical excision of the tumor, electrochemotherapy resulted in good local control and cosmetic appearance and should be added to the standard oncological therapies for avian.

Macrorhabdus ornithogaster Infection and Spontaneous Proventricular Adenocarcinoma in Budgerigars ( Melopsittacus undulatus)

Proventricular infection with the anamorphic, ascomycetous yeast Macrorhabdus ornithogaster and disease associated with infection (macrorhabdiosis) have been widely reported in budgerigars ( Melopsittacus undulatus). Proventricular adenocarcinoma has also been previously reported in this species. In a retrospective archival search of clinical cases submitted to a zoo animal and exotic pet pathology service between 1998 and 2013, a total of 28 128 avian submissions were identified, which included 1006 budgerigars kept in zoos or aviaries or as pets. Of these budgerigars, 177 were identified histologically as infected with M. orthithogaster at the time of necropsy. Histologic examination of tissues from budgerigars infected with M. orthithogaster identified an apparent continuum in the development of proventricular isthmus lesions associated with M. ornithogaster that included inflammation, mucosal hyperplasia, glandular dysplasia, and adenocarcinoma. Proventricular adenocarcinoma was identified histologically in 21 budgerigars. Budgerigars with proventricular adenocarcinoma were significantly more likely to have macrorhabdiosis than budgerigars without proventricular adenocarcinoma. Based on odds ratios for archival data, budgerigars were 41 times (95% confidence interval [CI], 33-52) more likely to have macrorhabdiosis than other avian species and 19 times (95% CI, 11-33) more likely to have proventricular adenocarcinoma than other birds. Budgerigars were 323 times (95% CI, 42-2490) more likely to be affected by both diseases simultaneously compared with other avian species. These findings suggest that macrorhabdiosis may be an associated factor for proventricular adenocarcinoma, although the explanation for this statistically significant correlation remains unknown and further investigation is warranted.

Subcutaneous Myxomas in Kelp Gulls ( Larus dominicanus) in Chile

Myxomas are an uncommon neoplasm in vertebrates, and are found at a low frequency in birds, both wild and domestic. We report myxomas in two Kelp Gulls ( Larus dominicanus) in Chile, identifying tumors in specimens that were received for necropsy.

Pleomorphic Malignant Mesothelioma in a Broiler Breeder Infected with Avian Leucosis Virus Subgroup J

Avian leucosis virus (ALV) is an oncogenic retrovirus that induces tumours including lymphoid leucosis and myeloid leucosis. Pleomorphic malignant mesothelioma and myelocytoma, which were thought to be induced by ALV subgroup J (ALV-J) infection, were identified in a 432-day-old broiler breeder. The bird showed no clinical signs; however, at necropsy examination there were multiple nodules in the alimentary tract. Microscopical analysis showed that these consisted of pleomorphic cells and myelocyte-like cells. Immunohistochemistry revealed that the pleomorphic cells were atypical and expressed cytokeratin, vimentin, c-kit, calretinin and ALV. The myelocyte-like cells were also positive for ALV. Retroviral type C particles were observed by electron microscopy. ALV-E and ALV-J nucleotide sequences were detected in DNA extracted from formalin-fixed and paraffin wax-embedded small intestinal tissue. Based on these results, the tumours were diagnosed as pleomorphic malignant mesothelioma and myelocytoma and were thought to have been induced by ALV-J infection. This is the first report of malignant mesothelioma associated with naturally acquired ALV-J infection.

Galliformes and Columbiformes

Galliformes and columbifomes are closely associated with humans and some species have been domesticated for well over 5000 years. Both orders remain diverse, ranging from the common domestic poultry species (e.g., chicken, turkey, and squabs) to the more exotic species found in the wild and in zoological collections. While many species have been benefited from human activities and have increased their ranges, others have declined in numbers and some have become threatened (e.g., Trinidad piping-guan and wood quail) or even extinct (e.g., dodo and passenger pigeon). Nondomestic galliformes and columbiformes are susceptible to many of the same diseases that occur in domestic species, yet predisposition may be different. Furthermore, disease prevalence depends on exposure and potential risk factors. Infectious diseases that tend to be more common under intensive commercial production may not pose as great a risk to exotic and free-living species.

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.

Cancer Prevalence and Etiology in Wild and Captive Animals

Neoplasia has been recorded in the vast majority of metazoans. The frequent occurrence of cancer in multicellular organisms suggests that neoplasia, similar to pathogens/parasites, may have a significant negative impact on host fitness in the wild. This is supported by the fact that wildlife cancers have recently been shown to result in significantly increased levels of mortality and concomitant reduction in fitness. By thorough searches of the available literature we provide a comprehensive and an updated list of cancer prevalence and etiology in the wild. We were, however, unable to find data on nontransmissible cancer prevalence in invertebrates and consequently this chapter focuses on cancer in wild vertebrates. Although single cases of cancer are frequently encountered in the wildlife, we were only able to retrieve robust data on cancer prevalence for 31 vertebrate species (12 fish, 3 amphibians, 2 reptiles, 2 birds, and 12 mammals). Cancer prevalence among these vertebrates ranged from as low as 0.2% observed in Canada geese (Branta canadensis) to more than 50% recorded in both Santa Catalina Island foxes (Urocyon littoralis catalinae) and Cape mountain zebras (Equus zebra zebra). The high prevalence recorded in some vertebrates strongly suggests that cancer in wildlife may indeed carry significant fitness costs. In spite of this, the low number of published comprehensive studies clearly shows that so far cancer in wildlife has received insufficient attention by biologists. We hope that this chapter will act as a catalyst for further studies focusing on the impact of cancer in wild animals. The chapter additionally compares cancer recorded in French zoological parks to those obtained at other zoological parks. Finally, we provide an updated list of cancer recorded as single cases in the wild, as well as in captive animals.

Systemic Clinical and Metabolic Diseases

Like other animals pet and companion birds are also prone to systemic illness. This is presented in the form of certain clinical signs and symptoms which is known as “ sick-bird syndrome.”

A 5-Year Retrospective Review of Avian Diseases Diagnosed at the Department of Pathology, University of Georgia

Avian samples (n = 827) submitted to the University of Georgia from 2006 to 2011 were reviewed to determine common disease entities and taxa-specific patterns. The study included 153 species, with 64.5% Psittaciformes, 11.3% Passeriformes, 7.9% Galliformes, 3.8% Columbiformes and 3.5% Anseriformes. Infectious agents were identified in 226 birds (27.3%); bacterial infections (n = 119; 14.4%) were most commonly gram-negative bacilli and Chlamydia psittaci and less commonly Mycoplasma and Mycobacterium spp. Mycotic infections (e.g. Aspergillus spp., Candida spp.) were identified in 66 birds (7.9%), followed by viruses in 30 birds (3.6%), most commonly polyomavirus and poxviruses. Eighteen birds had macroparasite infections, which were most common in Galliformes and most often involved gastrointestinal Capillaria spp. Neoplasia was diagnosed in 76 birds (9.2%) of 25 species, with 79% of the tumours deemed to be malignant. The most common neoplasm was lymphoma (n = 17; 22.4%), which was diagnosed in Psittaciformes, Galliformes and Passeriformes. Adenocarcinoma (n = 9) was found most frequently in the reproductive and gastrointestinal tracts. Haematopoietic neoplasms included myelocytoma and erythroid leucosis. Atherosclerosis was most common in psittacines (23/32; 71.8%) and in raptors and aquatic birds. Seventeen birds, mostly psittacines and aquatic birds, had amyloidosis, most often in the liver, kidney and spleen. Twenty-two birds had gout, most commonly the visceral form. Overall, bacterial infection was the most frequently diagnosed cause of death in captive birds, most commonly in Psittaciformes, followed by Passeriformes and Galliformes. Neoplasia was most common in Psittaciformes, which generally are longer lived than other taxa studied. Some disease entities (e.g. atherosclerosis and aspergillosis) may be associated with captive conditions, and some may involve a genetic predisposition (e.g. atherosclerosis, amyloidosis and haemosiderosis).

Record-Breaking Pain: The Largest Number and Variety of Forelimb Bone Maladies in a Theropod Dinosaur

Bone abnormalities are common in theropod dinosaur skeletons, but before now no specimen was known with more than four afflicted bones of the pectoral girdle and/or forelimb. Here we describe the pathology of a specimen of the theropod dinosaur Dilophosaurus wetherilli with eight afflicted bones of the pectoral girdle and forelimb. On its left side the animal has a fractured scapula and radius and large fibriscesses in the ulna and the proximal thumb phalanx. On its right side the animal has abnormal torsion of the humeral shaft, bony tumors on the radius, a truncated distal articular surface of metacarpal III, and angular deformities of the first phalanx of the third finger. Healing and remodeling indicates that the animal survived for months and possibly years after its ailments began, but its right third finger was permanently deformed and lacked the capability of flexion. The deformities of the humerus and the right third finger may be due to developmental osteodysplasia, a condition known in extant birds but unreported in non-avian dinosaurs before now.

Prevalence of Neoplastic Diseases in Pet Birds Referred for Surgical Procedures

Neoplastic disease is common in pet birds, particularly in psittacines, and treatment should be primarily aimed at tumor eradication. Nineteen cases of pet birds submitted to diagnostic and/or therapeutic surgical procedures due to neoplastic disease characterized by the presence of visible masses were retrospectively analyzed; affected species, types of neoplasms and respective locations, and outcomes of surgical procedures were determined. All birds undergoing surgery belonged to the order Psittaciformes; the Blue-fronted parrot (Amazona aestiva) was the prevalent species. Lipoma was the most frequent neoplasm in the sample studied. Most neoplasms affected the integumentary system, particularly the pericloacal area. Tumor resection was the most common surgical procedure performed, with high resolution and low recurrence rates.

"TERATOCARCINOMATOSIS" IN AN EMU (DROMAIUS NOVAEHOLLANDIAE)

An adult female emu (Dromaius novaehollandiae) with no previous abnormal clinical signs was found dead in its stall. A postmortem examination revealed carcinomatosis of unknown origin. Histopathology identified the masses as teratomas with malignant transformation by the presence of poorly differentiated tissue and dissemination throughout the coelomic cavity. We propose a new term, "teratocarcinomatosis," for this finding. This is the first case of a reproductive tumor described in an emu and the first case of such marked spread of malignant teratomas in a bird.

Bilateral Malignant Seminomas in Two Unrelated, Aged Trumpeter Hornbills (Bycanistes buccinator)

Seminomas occur infrequently in birds. Two cases of bilateral malignant seminomas in unrelated trumpeter hornbills (Bycanistes buccinator) are described. Case 1 was a 22-year-old trumpeter hornbill submitted for necropsy because of sudden death at a zoo in California. Postmortem examination revealed multiple masses within the body cavity, 2 of which replaced both testes. Case 2 was a 19-year-old trumpeter hornbill at a zoo in North Carolina that underwent exploratory surgery for a suspected gastrointestinal obstruction. Both testes were diffusely enlarged, compressing and replacing the adjacent kidneys. In both birds, the masses were composed of discrete, round to polyhedral cells, typical of seminomas. Examination of the ancestry of the hornbills showed they were unrelated to each other, suggesting a potential predisposition for these birds to develop seminomas.

Air sac adenocarcinoma of the sternum in a Quaker parrot (Myiopsitta monachus)

Respiratory neoplasia is rarely reported in avian species. A 17-yr-old Quaker parrot (Myiopsitta monachus) was admitted with a 2-wk history of anorexia, depression, and respiratory distress. Clinical examination revealed a large, firm mass in the left pectoral muscle. Radiology showed a mass silhouetting the heart and the liver. Supportive treatment was provided, but the bird died during the seventh weekly visit to drain thoracic cavity fluid. Necropsy showed a white, 3 x 3 x 2-cm, hard, gritty sternal mass. Histology showed a nonencapsulated, moderately differentiated air sac carcinoma of the sternum. Immunohistochemically the neoplasm was cytokeratin positive and vimentin and calretinin negative. This is the first report of an air sac neoplasia in a Quaker parrot and one of few respiratory tumors in psittacines.

Liposarcoma in animals: literature review and case report in a domestic pig (Sus scrofa)

Liposarcomas are malignant tumors of adipocytes. The current report describes a liposarcoma in a 2.5-year-old, mixed-breed commercial sow that was detected during meat inspection. On gross examination, a firm, whitish, multinodular, 20 cm ×10 cm mass was observed in the perirenal area along with smaller nodules multifocally scattered within the renal parenchyma. Histological examination revealed an anaplastic sarcoma with clear intracytoplasmic lipidic vacuoles that were positive for Sudan black staining. Most of the cells were also positive for S100 and vimentin immunohistochemistry. Based on these results, a diagnosis of a perirenal liposarcoma was established. To the authors' knowledge, no previous reports of liposarcomas in pigs have been published. This report also includes a review of the literature published on animal liposarcomas.

Sertolioma unilateral como causa de morte súbita por hemorragia interna em ganso Anser cygnoides

Um ganso adulto macho (Anser cygnoides), da família Anseriformes, de idade desconhecida, proveniente de uma criação da Universidade Luterana do Brasil, foi encontrado morto, sem apresentar histórico clínico, e foi submetido à investigação post mortem no Setor de Patologia Veterinária do Hospital Veterinário. Com base nos achados de necropsia e no exame histopatológico, definiu-se como causa da morte do animal hemorragia interna em razão da ruptura de vasos sanguíneos em uma neoplasia no testículo direito (sertolioma), com metástase no fígado.

Cloacolithiasis and intestinal lymphosarcoma in an African black-footed penguin (Spheniscus demersus)

A 13-yr-old male African black-footed penguin (Spheniscus demersus) presented thrice over 7 mo with gastrointestinal obstruction secondary to cloacolithiasis. Clinical signs consistently resolved with cloacolith removal and supportive care. However, 10 mo after initial presentation, it presented with similar signs, plus significant weight loss. No cloacolith was found, and it subsequently died. Significant gross findings included bilateral cecal masses, colonic perforation, and marked secondary coelomitis, multifocal tan to pale hepatic nodules, and pale kidneys with miliary white foci. Histopathologic diagnoses were intestinal lymphosarcoma with hepatic and renal metastases, secondary intestinal rupture, and subacute severe bacterial coelomitis. To the authors' knowledge, this is the first full report of either cloacolithiasis or lymphosarcoma in a penguin.

Peripheral nerve sheath tumor in a subadult golden eagle (Aquila chrysaetos)

A 5-year-old, female golden eagle (Aquila chrysaetos) was admitted with tetraplegia that progressed to a nonambulatory, spastic tetraparesis after a few days of treatment. Clinical and radiologic examinations, including radiography, computed tomography scan, and myelography, were indicative of neoplasia involving a spinal nerve root. Postmortem magnetic resonance imaging and necropsy findings confirmed the diagnosis of a peripheral nerve sheath neoplasia, not, to our knowledge, previously reported in a raptor.

Osteoma in a blue-fronted Amazon parrot (Amazona aestiva)

Osteoma is an uncommon bone formation documented in avian species and other animals. A blue-fronted Amazon parrot (Amazona aestiva) with clinical respiratory symptoms was examined because of a hard mass present on the left nostril. Radiographs suggested a bone tumor, and the mass was surgically excised. Histopathologic examination revealed features of an osteoma. To our knowledge, this is the first description of an osteoma in a blue-fronted Amazon parrot. Osteoma should be considered as a differential diagnosis in birds with respiratory distress and swelling of the nostril.

A case of cutaneous angiolipoleiomyoma (angiomyolipoma) in a budgerigar (Melopsittacus undulatus)

We report a case of cutaneous angiolipoleiomyoma (angiomyolipoma) found on the anterior wall of the ventral part of the abdomen of a three-year-old female budgerigar (Melopsittacus undulatus). Histologic examination of the well-circumscribed, surgically removed tumour (1.5 cm in diameter) showed a benign admixed proliferation of blood vessels of different size, smooth muscle bundles, and mature adipose tissue, without evidence of malignancy. Endothelial cells of the haemangioma component were positive for claudin-5 endothelium-specific immunohistochemical marker, and the leiomyoma component was positive for α-smooth muscle actin. The differentiated lipocytes showed S-100 protein positivity. The Ki-67 labelling index was 2 to 3%. The mesenchymal tumour was negative for HMB45 melanocytic immunhistochemical marker. To the best of our knowledge, this is the first report describing a cutaneous angiolipoleiomyoma in a budgerigar with histological and immunohistochemical analyses.

A complicated, metastatic, humeral air sac cystadenocarcinoma in a timneh African grey parrot (Psittacus erithacus timneh)

A 9-year-old male timneh African grey parrot (Psittacus erithacus timneh) was presented because of inability to fly and suspected trauma. The owner also had observed dyspnea, with tail bobbing and open-beak breathing. On clinical examination, a hard, painful mass was palpable in the left proximal humerus and axillary area. Radiographs revealed a radiodense soft tissue mass of the left humerus with no bony involvement, multifocal opacities in lung and air sacs, and an enlarged spleen. An asymmetric, vascularized cyst was detected in the mass by ultrasound examination. Results of biopsy of the mass revealed multifocal cysts composed of unilayer isoprismatic cells laying in vascularized connective tissue. Because of the severity of clinical signs and the poor clinical condition, the bird was euthanatized. On postmortem examination, the findings were air sac cystadenocarcinoma involving the humeral air sac with metastases in the spleen and kidneys, atherosclerosis, pneumoconiosis, and mycotic granulomatous pneumonia and airsacculitis with isolation of Aspergillus niger.

Naturally occurring neoplasms in pigeons in a research colony: a retrospective study

This study reports the gross and microscopic pathology of naturally occurring neoplasms in adult pigeons that were presented for necropsy at the Indiana Animal Disease Diagnostic Laboratory from 2001 to 2011. The study population consisted of white carneau and mixed-breed pigeons used in behavioral studies in the Department of Psychological Sciences at Purdue University. Twelve types of neoplasms or proliferative disorders were identified in 28 of 83 pigeons (33.7%). Five pigeons had two or three types of neoplasms-proliferative disorders. Of the 83 pigeons, 11 (13.3%) had seminoma, five (6.0%) had thyroid adenoma, four (4.8%) had lymphoma, four (4.8%) had adenocarcinoma of female reproductive tract origin, two (2.4%) had pulmonary carcinoma, and two (2.4%) had cutaneous vascular hamartomas. Also identified were single incidences of dysgerminoma, mesothelioma, liposarcoma, cloacal papilloma, cloacal adenocarcinoma, and gizzard carcinoma. The most frequently occurring tumor was seminoma; 7/11 cases effaced both testicles and 3/11 cases had metastasis to the liver or kidney. The relatively high prevalence of neoplasms in pigeons in the present study is most likely related to the advanced ages of pigeons kept in the research colony.

Malignant sertoli cell tumor in a goose (Anser cygnoides domesticus)

This paper describes the pathologic features of a malignant Sertoli cell tumor found in an adult goose (Anser cygnoides domesticus). At necropsy, in addition to one large tumor mass (15 cm in diameter), multiple small tumor masses were observed over the peritoneum and mesenterium in the coelomic cavity. The large tumor mass was composed of sheets, lobules, and small islands of tumor cells, and elongated tumor cells lying perpendicular to fibrous connective tissue were characteristic. Such histopathologic characteristics were common to all the tumors. The tumor cells were immunohistochemically positive for neuron-specific enolase and S-100, and some tumor cells contained fine intracytoplasmic pigments that stained red by oil red O staining. These findings, taken together with the fact that one testis was markedly atrophied and bore no tumor cells and the other testis was not discernible, the present case was diagnosed as unilateral malignant Sertoli cell tumor arising from the unilateral testis. To our knowledge, this is the first report of Sertoli cell tumor in the goose.