Choriocarcinoma : HCG
Immunohistochemistry of Choriocarcinoma: Syncytiotrophoblasts express hCG, human placental lactogen, inhibin, and glypican 3.
Cytotrophoblasts are positive for SALL4, GDF3, p63, and GATA3. hCG staining is strongest in syncytiotrophoblasts and weak or absent in cytotrophoblasts.
Other positive markers in choriocarcinoma include: PLAP (50% of cases); CEA (25% of cases); EMA (50% of cases); and cytokeratins 7, 8, 18, and 19.
The image shows strong immunoreactivity for hCG in syncytiotrophoblasts and large mononucleated trophoblastic cells.