Congenital ascites due to hepatoblastoma with extensive peritoneal implantation metastases in a premature equine fetus.

This research article describes the case of a prematurely deceased equine (horse) fetus with a large liver tumor, identified as hepatoblastoma, and extensive metastases affecting the peritoneal cavity.

Investigation of the Case

• The study begins with the delivery of a premature horse fetus that had abnormalities in its abdomen, specifically an enlarged and fluctuating distension. This abnormality prompted an examination after death (post-mortem) to determine the problem.
• During this examination, a yellow lump about 25 cm in diameter was found in the right lobe of the liver, which was irregular and firm with multiple nodules. This mass was out of the ordinary and indicative of a serious condition.
• Alongside this mass were a notable presence of ascites – a build-up of fluid in the abdominal cavity – and widespread abnormalities termed as peritoneal implantation metastases, an indication of cancer spread within the abdomen.

Diagnosis of Hepatoblastoma

• The tumor cells in the mass were polygonal embryonal cells, a type of primitive cell found in embryonic or fetal tissue. They were arranged in a pattern of sheets and nests, typical of certain types of tumors.
• To confirm the diagnosis, the researchers used immunohistochemistry, a method that uses antibodies to identify certain proteins in the tissue sample. This technique was used to examine three proteins: Ki67, a protein related to cell proliferation; low molecular weight cytokeratin, a type of protein common in epithelial cells; and alpha-1 fetoprotein, a substance produced by certain tumors, including hepatoblastoma.
• Based on the expression of these proteins, a diagnosis was made: the mass was identified as hepatoblastoma, a type of liver cancer most often seen in infants and children, with metastases implanted in the peritoneal lining.

Significance of the Case

• This case is significant as it adds to the body of knowledge regarding hepatoblastoma, a rare form of liver cancer. It is unusual to identify this condition in an equine fetus, and the information gathered from this case could inform future studies on similar issues.
• In addition, the findings may also be helpful for veterinary practice, particularly when it comes to recognizing and diagnosing liver conditions in equine fetuses.