A baby is born with a testicular mass. Histologic sections made of the homogeneous yellow white mass after its removal demonstrate epithelial-lined spaces that have flattened-to-cuboidal epithelial cells with vacuolated cytoplasm containing eosinophilic, hyaline-like globules. Scattered structures resembling primitive glomeruli (endodermal sinuses) are also seen. If appropriate immunohistochemical stains are performed, the eosinophilic cytoplasmic globules would most likely contain which of the following?

The malignant tumor is a yolk sac tumor, also known as infantile embryonal carcinoma and endodermal sinus tumor. The biggest tip-off in the question stem is the presence of endodermal sinuses that resemble primitive glomeruli. The cytoplasmic globules described contain alpha-fetoprotein, indicating yolk cell differentiation, and alpha-1-antitrypsin. Alpha-fetoprotein can also be used as a serum marker for recurrent disease. Yolk sac tumors occur in pure form in infants and children and may be pa of mixed tumours in adults.Estrogen receptors are impoant markers in breast cancer because they predict tumor response to hormonal manipulation. Human chorionic gonadotropin is found in the syncytial cells of embryonal carcinoma. Human papillomavirus can be found in condylomas, cervical cancer, penile cancer, laryngeal polyps, and was. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 13. Prenatal Diagnosis and Fetal Therapy. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.