AFP and teratoma: Six patients initially diagnosed with teratomas (mature, n=3; immature, n=4) relapsed with malignant yolk sac elements confirmed by raised AFP and/or histology, two were extragonadal and four ovarian. Biochemical progression preceded clinical or radiological relapse in 41 (80.3%), while 10 non-secretory GCTs relapsed on imaging or histology.