Testicular yolk sac tumors (also known as endodermal sinus tumor of the testis) is the most common childhood testicular tumor (80%), with most cases occurring before the age of two years 1. In adults, pure yolk sac tumor is extremely rare, however mixed germ cell tumor are commonly seen.
Totipotent cells, which later form extraembryonic fetal membranes, give rise to yolk sac tumors.
Perivascular structures called Schiller-Duval bodies can be found in 50% of tumors and are pathognomonic.
AFP (alpha fetoprotein) is elevated in >90% cases of yolk sac tumor. Macroscopically, the testis is replaced by a gelatinous mass. Microscopically, a positive reaction for AFP is seen in tumor cells.
Prospective radiologic characterization of yolk sac tumor is difficult, however a heterogeneous testicular mass favors non-seminomatous germ cell tumor (NSGCT), and at age <2 years, yolk sac tumor is the favored diagnosis.
Diffusely enlarged heterogeneous testis.
Heterogeneous testicular mass lesion with post-contrast heterogeneous enhancement, with areas of hemorrhage/necrosis 2.
Treatment and prognosis
If the tumor is restricted to the testis, and if the serum AFP is not elevated, orchiectomy is the preferred treatment, with close follow-up. If relapse occurs, chemotherapy is the treatment of choice. The lungs are the most common site of recurrence.
- 1. Woodward PJ, Sohaey R, O'donoghue MJ et-al. From the archives of the AFIP: tumors and tumorlike lesions of the testis: radiologic-pathologic correlation. Radiographics. 22 (1): 189-216. Radiographics (full text) - Pubmed citation
- 2. Tsili AC, Tsampoulas C, Giannakopoulos X et-al. MRI in the histologic characterization of testicular neoplasms. AJR Am J Roentgenol. 2007;189 (6): W331-7. doi:10.2214/AJR.07.2267 - Pubmed citation
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