Retroperitoneal Endodermal Sinus Tumor
Germ cell tumors can be divided into seminomas and non-seminomatous tumors, which include embryonal carcinomas, endodermal sinus tumors, choriocarcinomas, teratomas, and mixed germ cell tumors. The vast majority originates in ovary and testis gonads, and a small number occurs beyond gonads. Retroperitoneum is the second most common site of extragonadal germ cell tumors. Primary retroperitoneal extragonadal germ cell tumors are rarely encountered neoplasms that occur without an apparent gonadal primary lesion. Primary retroperitoneal endodermal sinus tumor (PREST), also known as primary retroperitoneal yolk sac tumor (PRYST), is an extremely rare tumor that has only previously been described in case reports and occurs principally in girls and women of childbearing age.