YOLK-SAC TUMOR WITH A UNIQUE UNIFORM HEPATOID PATTERN HISTOLOGY

Background: Yolk sac tumors (YST) exhibit several different histologic al subtypes and the mechanisms of cellular differentiation and prognos is of each subtype remain unknown. Results: We report two infants with sacrococcygeal YST; one represented a typical histological subtype an d the other showed a hepatoid subtype with uniform histology. The isof orm of alpha fetoprotein (AFP) in the patient with the hepatoid patter n was examined by lectin-affinity immunoelectrophoresis and represente d as a YST, but not hepatocellular, subtype. The patient with typical YST responded well to VAB-6 combination chemotherapy. However, this re gimen was only partially effective to the patient with the pure hepato id histological subtype, and an etoposide with ifosfamide and cisplati n (VIP) regimen as a salvage chemotherapy combined with complete tumor resection was useful to achieve complete remission (CR). Both of the patients have been in CR for more than four years.