A 25 year old man undergoes orchiectomy for a testicular tumor. Microscopically, the tumor shows a variety of patterns, including lobules containing large cells with watery cytoplasm, structures resembling primitive glomeruli, syncytiotrophoblast, and shafts of undifferentiated cells with focal glandular differentiation. Which of the following terms most accurately describes this tumor?
Choriocarcinoma Embryonal carcinoma Mixed tumor Seminoma