Cetacean "gas-bubble thromboembolic polycystic liver disease": "Budd-Chiari-like syndrome" in dolphins?

Nearly two decades ago, pathologic examination results suggested acoustic factors, such as mid-frequency active naval military sonar (MFAS) could be the cause of acute decompression-like sickness in stranded beaked whales. Acute systemic gas embolism in these beaked whales was published together with enigmatic cystic liver lesions (CLL), characterized by intrahepatic encapsulated gas-filled cysts, tentatively interpreted as "gas-bubble" lesions in various cetacean species. Here we provide a pathologic reinterpretation of CLL in cetaceans. From 1,200 cetaceans necropsied, CLL were only observed in striped dolphins (Stenella coeruleoalba), with a low prevalence (2%), and recapitulated pathologic features of Budd-Chiari syndrome in humans. Our results strongly suggest that CLL are the result of the combination of pre-existing or concomitant hepatic vascular disorder (e.g., severe hepatobiliary trematodiasis) superimposed and exacerbated by gas bubbles, and clearly differ from acute systemic gas embolism in stranded beaked whales linked to MFAS.