Two cases of primary yolk sac tumor of the liver in childhood: case reports and literature review.

Primary yolk sac tumor of the liver is an extremely rare neoplasm, with fewer than 20 cases reported. We evaluated 2 pediatric cases (21-month-old and 23-month-old female patients), who presented with liver masses and markedly raised serum alpha-fetoprotein (AFP). One patient received a partial hepatectomy and another patient underwent a liver biopsy, both of which showed characteristic features of yolk sac tumor, with tumor cells staining strongly positive for AFP. There was no evidence of an extrahepatic primary source. Both of our patients have been healthy, without evidence of recurrent tumor, and their AFP level remains in the normal range after their chemotherapeutic treatments.