An endodermal sinus tumor (yolk sac tumor) of the testis is shown composed of primitive germ cells that form glomeruloid or embryonal-like structures.

• 睾丸的内胚层窦肿瘤（卵黄囊肿瘤）由原始生殖细胞构成，这些细胞形成血管球或胚芽样结构。