Rarely, liver tissue can be seen in the umbilical cord, where it is thought to result from ectopic localization during embryogenesis. The placental parenchyma is also a rare site for this occurrence. The exact pathophysiology of ectopic liver in the placenta is unknown. It has been considered that aberrant migration or displacement of cells from the developing hepatic buds leads to ectopic liver formation, including groups of liver cells that become entrapped in the foregut as the diaphragm closes. Additional hypotheses put forward have included monodermal teratoma and hepatocellular adenoma. While the lesions may not actually be adenomas, this term has been most utilized in the literature. Hepatocellular adenomas of the placenta are extremely rare; only 9 cases have been reported thus far. We report an additional occurrence of ectopic liver in the placenta, which is the only one reported in a stillborn, and review the literature.
Keywords: ectopic liver; hepatic adenoma; monodermal teratoma; placenta; placental neoplasm.