Brief Report: A Second Primary Endodermal Sinus Tumor 9 Years after Initial Diagnosis

Background: Ovarian yolk sac tumors (YSTs) are rare malignant germ cell tumors known to present unilaterally, allowing for fertility-sparing surgical treatment with adjuvant chemotherapy. The few published cases of bilateral ovarian involvement were at the time of original diagnosis in patients with widely metastatic disease. We present, to our knowledge, the first case of bilateral ovarian YSTs, diagnosed several years apart, and discuss the implications on recurrence and tumor marker surveillance for these tumors. Case: This is a case of a young woman who re-presented 9 years after initial treatment, with a YST in the contralateral ovary. Summary and Conclusions: YSTs are well established as unilateral tumors, however, in rare cases such as this, they might reappear years later on the contralateral ovary.