Neoplasia in Felids at the Knoxville Zoological Gardens, 1979–2003

Abstract

A review of medical records and necropsy reports from 1979-2003 found 40 neoplasms in 26 zoo felids, including five lions (Panthera leo, two males and three females), three leopards (Panthera pardus, two males and one female), one jaguar (Panthera onca, female), 11 tigers (Panthera tigris, three males and eight females), two snow leopards (Panthera uncia, one male and one female), two cougars (Felis concolor, one male and one female), one bobcat (Felis rufus, male), and one cheetah (Acinonyx jubatus, female). Animals that had not reached 3 yr of age or had been housed in the collection less than 3 yrs were not included in the study. Neoplasia rate at necropsy was 51% (24/47), and overall incidence of felid neoplasia during the study period was 25% (26/103). Neoplasia was identified as the cause of death or reason for euthanasia in 28% (13/47) of those necropsied. Neoplasms were observed in the integumentary-mammary (n=11), endocrine (n=10), reproductive (n=8), hematopoietic-lymphoreticular (n=5), digestive (n=3), and hepatobiliary (n=2) systems. One neoplasm was unclassified by system. Multiple neoplasms were observed in 11 animals. Both benign and malignant neoplasms were observed in all systems except for the hematopoietic-lymphoreticular systems where all processes were malignant. Of the endocrine neoplasms, those involving the thyroid and parathyroid glands predominated (n=8) over other endocrine organs and included adenomas and carcinomas. In the integumentary system, 63% (7/11) of neoplasms involved the mammary gland, with mammary carcinoma representing 83% (6/7) of the neoplasms. The rates of neoplasia at this institution, during the given time period, appears to be greater than rates found in the one other published survey of captive felids.