Ovarian endometrioid-like yolk sac tumor treated by surgery alone, with recurrence at 12 years

We describe the case of a stage Ia endometrioid-like yolk sac tumor (YST) of the ovary, which was originally misdiagnosed as a malignant struma ovarii and not treated with adjuvant chemotherapy. After 12 years, a contralateral dermoid cyst was excised along with a small omental nodule of partially necrotic and calcified endometrioid-like YST. No tumor was detected in several other biopsy specimens, and a peritoneal lavage was negative for tumor cells. Since there was no evidence of remaining tumor and the serum alpha-fetoprotein (AFP) level was normal after the second operation, the patient was followed. Serial serum AFP levels remained normal for 4 months. At a second-look laparotomy after 4 months, a small tumor nodule was removed from the cul-de-sac. Postoperatively, the patient received three cycles of BEP chemotherapy. The long disease-free interval after the first operation in spite of the presence of occult spread to the omentum and to the pouch of Douglas in this case indicates that some endometrioid-like YSTs may have an indolent course. The present case underscores the importance of careful surgical staging and of long-term follow-up in cases of primitive germ cell tumors of the ovary.