Subcutaneous, Abdominal, And Thoracic Encapsulated Fat Necrosis In Bowhead Whales Balaena Mysticetus From Alaska, Usa Diseases of Aquatic Organisms

Wedescribeacaseseriesofencapsulatedfatnecrosiswithsubcutaneous,abdominal, andthoraciclocationsin7subsistence-harvestedbowheadwhalesBalaena mysticetus.Masseshad a variably-dense fibrous capsule surrounding necrotic adipocytes and calcium salts (saponification). One animal also had prior concussive injury, pleural fibrosis, and hepatic lipoma; the other animals had no significant findings. The described condition is uncommon in bowhead whales, with 7/575 (1.2%) observed from 1996 to 2015. The exact mechanisms of development of encapsulated fat necrosis in bowhead whales remain to be determined. Encapsulated fat necrosis has been reported in other baleen whales, humans, and cows. It is usually an incidental finding during post-mortem examination that needs to be differentiated from neoplastic and inflammatory lesions, as the latter may have public health implications. Assessment of further cases in bow-head whales and other baleen whales is warranted to better understand their pathogenesis.