For embryonal carcinoma, which marker is NOT part of the panel?

• A. Chromogranin
• B. Synaptophysin
• C. SOX2
• D. CD30

Answer: (A)

Embryonal carcinoma is identified by a profile that reflects its primitive epithelial/embryonal nature: it typically shows CD30 positivity, cytokeratin positivity, and OCT3/4 positivity, with SOX2 often expressed as well. These markers help distinguish it from seminoma and other germ cell tumors. Neuroendocrine markers belong to a different diagnostic realm; chromogranin A is a classic neuroendocrine marker, so its positivity would steer you toward a neuroendocrine tumor rather than embryonal carcinoma. That’s why chromogranin is not part of the standard embryonal carcinoma panel, whereas the other markers can be, reflecting the tumor’s germ cell and embryonal differentiation.