Spontaneous proliferative and neoplastic lesions in thyroid and parathyroid glands of nondomestic felids

Use of oral chemotherapeutic agent, chlorambucil, as palliative treatment of thryoid adenocarcinoma in a golden-headed lion tamarin (Leontopithecus chrysomelas)

This case report describes the use of chlorambucil in a 7.5-year-old golden-headed lion tamarin (Leontopithecus chrysomelas) as palliative therapy for thyroid adenocarcinoma. Treatment was initiated at 0.1 mg/kg orally once daily. No physical abnormalities or substantial changes in complete blood cell counts and thyroid hormone levels from serial samples were detected.

MELANOCYTIC NEOPLASIA IN PANTHERA SPECIES: CLINICAL PRESENTATIONS, PATHOLOGIC FINDINGS AND RESPONSES TO TREATMENT

Neoplasia is a common cause of morbidity and mortality in captive nondomestic felids. Seven tigers (Panthera tigris), two African lions (Panthera leo), and two snow leopards (Panthera uncia) were diagnosed with melanocytic neoplasia (10 malignant melanomas, two benign melanocytomas) over a 20-yr period. Animals were 10-19 yr old and 5/7 tigers were phenotypically white. Malignant melanoma tumor location included skin (n = 4), oral mucosa (n = 2), nasal planum (n = 1), iris/uvea (n = 2), and lip margin (n = 1); melanocytomas were found in skin (n = 2). Metastasis to regional lymph nodes was seen at diagnosis in 3/7 melanoma cases. Thoracic radiography (n = 6) and/or computed tomography (n = 2) did not detect pulmonary metastasis at diagnosis but were useful for detection later in the disease course. Median survival time (MST) for all cases ranged from 1 mon - 40 mon. Seven cases with malignant melanoma underwent treatment, which included surgery, radiation therapy, and administration of the canine melanoma vaccine (Oncept^®) or a combination of these treatments; MST was 5-40 mon for these cases. While multimodal therapy may provide an improved survival time, the majority of animals with malignant melanoma invariably died from neoplastic disease. Necropsy confirmed metastasis of malignant melanoma in 7/9 animals; sites included lung, liver, lymph node, kidney, mesentery, pleural cavity, heart, stomach, spleen, and adrenal gland. This case series describes the clinical and histologic findings of melanocytic neoplasia in nondomestic felids as well as multimodal treatment strategies incorporating the canine melanoma vaccine.

An Overview of Neoplasia in Captive Wild Felids in Southern Italy Zoos

The aim of this study was to evaluate the frequency of neoplasms in captive wild felids in Southern Italy zoos over a 13-year period (2008–2021) and to investigate macroscopic and histologic tumor findings in these animals. A total of 24 cases were necropsied, 9 males and 15 females, with age ranging from 6 to 19 years, including 12 tigers (Panthera tigris), 7 leopards (Panthera pardus), 4 lions (Panthera leo), and 1 black jaguar (Panthera onca). Diagnosis of neoplasm was made in 14/24 cases (58.3%). Tumors diagnosed were two cholangiocarcinomas, two hemangiosarcomas of the liver, two uterine leiomyomas, a renal adenocarcinoma, an adrenal gland adenoma, a thyroid carcinoma, an oral squamous cell carcinoma, an osteoma, a meningioma, a mesothelioma, an esophageal leiomyosarcoma, a muscoloskeletal leiomyosarcoma and a thyroid adenoma. The malignant and benign tumors were 62.5 and 37.5%, respectively. Among malignant tumors, no metastasis was observed in 50% of cases; in 10% of cases metastasis involved only regional lymph nodes; and distant metastases were found in 40% of cases. Based on our findings, the liver was the most frequent primary tumor site (25%). The high rates of malignant and widely metastatic neoplasms suggest the importance of active monitoring and management of neoplasia in these threatened and endangered species.

A RETROSPECTIVE STUDY OF NEOPLASIA IN NONDOMESTIC FELIDS IN HUMAN CARE, WITH A COMPARATIVE LITERATURE REVIEW

This retrospective study of neoplasia in nondomestic felids in human care presents the cases diagnosed at Northwest ZooPath (NWZP), Monroe, Washington, from 1998 to 2017 in conjunction with a scoping literature review. The 554 neoplasms identified in 20 species in the NWZP archive were combined with the 984 neoplasms identified in those same species in the published literature. Some of the cases identified in the literature were from the NWZP archive. Based on this review, mammary adenocarcinoma (183/1,483, 12.3%), lymphoma (89/1,483, 6.0%), squamous cell carcinoma (85/1,483, 5.7%), pheochromocytoma (57/1,483, 3.8%), and thyroid adenoma (57/1,483, 3.8%) are the most frequently reported neoplasms in nondomestic felids in human care. Apparent species predilections for neoplasia include mammary adenocarcinoma in tigers, jaguars, lions, and jungle cats; lymphoma in lions and tigers; squamous cell carcinoma in snow leopards; pheochromocytoma in clouded leopards; ovarian adenocarcinoma in jaguars; cholangiocarcinoma in lions and tigers; multiple myeloma in tigers; bronchoalveolar adenocarcinoma in cougars and lions; hemangiosarcoma, hepatocellular carcinoma, and gastrointestinal adenocarcinoma in lions; mesothelioma in clouded leopards, lions, and tigers; myelolipoma and cutaneous mast cell tumor in cheetahs; soft tissue sarcomas in tigers; and transitional cell carcinoma of the urinary bladder in fishing cats.

Pathological and Immunohistochemical Characterization of Thyroid Neoplasms in Cats

There are few pathological and immunohistochemical descriptions of thyroid neoplasms in cats. We investigated neoplasms of the thyroid in 31 cats (average age 15.6 years) in Southern Brazil. Most (96.8%) of these cases were classified as follicular adenomas and were predominantly unilateral and multinodular. Histologically, macrofollicular adenomas were the most common type observed. Carcinomas represented 3.2% of the investigated tumours. By immunohistochemical labelling, thyroglobulin was expressed more commonly than paired box gene 8 or thyroid transcription factor 1 in the follicular adenomas. One carcinoma was immunopositive for thyroglobulin, pancytokeratin, chromogranin A and synaptophysin, suggestive of a calcitonin-negative neuroendocrine carcinoma.

The occurrence of cancer in vertebrates: a mini review

Neoplasia is a multilevel condition caused by irregularities over the genome, which can lead to a fatal result. To fully understand this phenomenon, an evolutionary challenge has risen during the last decades, away from human limits, driving the scientific quest into the wild life. The study of wild vertebrate populations in their natural habitats has shown that cancer is rather prominent. Thus, the diversity of vertebrates reported with some form of neoplasia is quite scattered through a variety of habitats. However, some species constitute exceptions by exhibiting cancer-protective features, driven by certain loci in their DNA. It is obvious that from an evolutionary standpoint, the incidence of cancer in different taxa is nowadays studied by seeking for patterns and their roots. The main purpose of the evolutionary approach is no other than to answer a fundamental question: Could cancer be ultimately regarded as another evolutionary force conducive to the formation or shaping-up of species?

Causes of morbidity in captive African lions (Panthera leo) in North America, 2001-2016

The lion (Panthera leo) is an iconic resident of zoos and wild animal parks throughout the world. Regular assessment of the morbidity of captive lions is necessary to address wellness concerns and improve the healthcare and management of this vulnerable species. In an effort to understand disease morbidity broadly and guide future inquiries into captive lion health, we distributed a questionnaire that emphasized diseases of organ systems rather than individual diagnoses. We sent the questionnaire to 108 American Zoo and Aquarium Association (AZA) institutions housing lions between 2001 and 2016. Fifty-six facilities responded of which 32 responses had usable data for 111 lions. Responses were compiled and analyzed with respect to age, class, and sex. Neoplasia, renal disease, and dental disease were the most common causes of morbidity in these captive lions. Older animals generally experienced a higher prevalence of multiple types of disease. Three cases of hypertrophic cardiomyopathies (HCM) were reported in nearly 40% (3/8) of cardiovascular diseases and 3% (3/111) of disease cases overall, which is the first report of HCM in lions, to the authors' knowledge. There is a relative paucity of literature on lion and large felid cardiovascular conditions, which suggests that this may be an understudied area of lion health. This broad assessment of morbidities present in captive lion populations aimed to identify key areas for further research and screenings. Management priorities of captive lions should include prevention strategies for dental disease and trauma, frequent screening for renal disease and neoplasia, and further research into cardiovascular health.