Cholangiocellular adenoma in Franciscana dolphins (Pontoporia blainvillei)

Pontoporia blainvillei, commonly known as the Franciscana dolphin, inhabits the coastal waters of South America and is classified as vulnerable and as undergoing significant population declines. This species is generally found in turbid coastal waters, although it is also found in clear waters, as well as marine areas associated with islands and rocky shores. Tumours originating from cholangiocytes have been rarely described in cetaceans, with descriptions limited to cholangiocellular carcinomas. Cholangiocellular adenomas are characterised by the formation of bile ducts and are rarer than cholangiocellular carcinoma. This study described the first report of a tumour originating from cholangiocytes in P. blainvillei, raising concerns on this endangered cetacean's health status and conservation. The underlying causes of this tumour in Franciscana dolphins remain unknown, highlighting the need for further research.