Yolk Sac Tumor : Immunostains - AFP

Comments:
Immunohistochemical profile of Ovarian Yolk Sac Tumor (YST): Both glypican-3 and AFP are strongly positive and are useful diagnostic markers of yolk sac tumor; however, Glypican 3 is more sensitive than AFP (100% +ve vs 80% +ve). Other positive markers include KIT, SALL4, cytokeratin AE1/AE3, and CAM5.2.

CEA is positive in areas of intestinal and endometrioid differentiation. Areas of intestinal differentiation are also positive for CDX2. HepPar-1 stains foci of hepatoid differentiation. Parietal foci stain for laminin and collagen IV. GATA-4, a transcription factor, is expressed in pediatric cases.

Important negative markers include CD30, OCT4, CK7, EMA, PAX8, ER, PR, D2-40, and WT1. A combination of SALL4 positivity and OCT4 negativity is considered to be highly specific for yolk sac tumor.