Endodermal Sinus Tumors

Endodermal sinus tumors (EST) have also been referred to as yolk sac carcinomas, because they are derived from the primitive yolk sac. These lesions are the third most frequent malignant germ cell tumor of the ovary. Endodermal sinus tumors occur at a median age of 18 years, and about one third of the patients are premenarchal at the time of presentation. Like the other nondysgerminomatous ovarian malignancies, abdominal or pelvic pain is the most frequent presenting symptom, occurring in about 75% of patients. An asymptomatic pelvic mass is documented in about 10% of patients.

Most EST lesions secrete AFP and rarely they may produce detectable AAT. There is a good correlation with the extent of disease and the AFP level, although discordance has been observed. The serum level of AFP is particularly useful in monitoring the patient during and after treatment.

Surgery
The treatment of EST includes a surgical exploration, a unilateral oophorectomy, and a frozen section for diagnosis. Any gross metastases should be removed if possible, but a thorough surgical staging is not necessary because all patients need chemotherapy. The tumors tend to be solid and large, ranging in size from 7 to 28 cm (median is 15 cm). The EST is thought never to be bilateral, and the other ovary will have metastasis only when there are other metastases in the peritoneal cavity. Most patients have early-stage disease: 71% have stage I, 6% have stage II, and 23% have stage III. The performance of a hysterectomy and contralateral salpingo-oophorectomy does not alter outcome.