Mesenchymal hamartomas of the liver may be associated with increased serum alpha foetoprotein concentrations and mimic hepatoblastomas.

A mesenchymal hamartoma (MH) of the liver in a seven-month-old girl was associated with slightly elevated alpha fetoprotein (AFP) concentrations (320 microg/L, normal < 25 after six months of age). Hepatocytes were abundant at the periphery of the tumour at histopathological examination. These were slightly atypical and expressed AFP immunohistochemically. In two other girls, aged 14 months and two months respectively, with MH and increased serum AFP concentrations (320 microg/L and 7500 microg/L, respectively), hepatoblastomas were misdiagnosed preoperatively. MH of the liver with increased serum AFP concentrations may thus mimic hepatoblastoma radiologically if cysts are lacking, and foetal hepatoblastoma pathologically if a biopsy samples only the peripheral hepatocellular component of the MH.