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Polyembryoma and Diffuse Embryoma

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  • Rare variants of mixed GCT (embryonal carcinoma + yolk sac tumor).


    • Yolk sac and embryonal carcinoma combine to form embryoid bodies (image A).
    • Embryoid bodies consist of a central disk of cuboidal embryonal carcinoma cells, a ventral yolk sac tumor component forming a yolk sac-like vesicle, and a dorsal amnion-like space, surrounded my myxoid stroma.
    • Patients may have elevated AFP levels, reflecting the yolk sac tumor component.

Diffuse embryoma

    • Consists of a delicate, almost lace-like intimate admixture of embryonal carcinoma and yolk sac tumor (image B).
    • Yolk sac tumor wraps around embryonal carcinoma component.