Tumors in Cetaceans: Analysis and New Findings

Abstract

We describe 14 tumors, including 5 leiomyomas, 6 papillomas, 2 adrenal adenomas, and a bronchogenic carcinoma collected from over 1800 free-ranging and captive cetaceans examined since 1973. These bring to 41 the number of confirmable tumors reported from cetaceans. Of the 52 cases previously reported, 23 were described in sufficient detail to confirm the diagnoses, 15 were considered probable, and 4 were reclassified. Organ systems most commonly affected were the gastrointestinal tract (31%), skin (24%), and female reproductive tract (21%). Sampling bias may account for this apparent trend. Etioiogic agents have rarely been identified, and attempts to do so are hampered by inadequate sample sizes.