Advanced extragonadal yolk sac tumor serially followed up with (18)F-fluorodexyglucose-positoron emission tomography and computerized tomography and serum alpha-fetoprotein.

Although yolk sac tumors (YSTs) are the second most common malignant germ cell tumor of the ovary, those arising from the omentum or pelvic peritoneum are extremely rare and have no established treatment guidelines. We report a case of a primary YST disseminated throughout the abdomen and associated with a high serum alpha-fetoprotein (AFP) elevation (441 611 ng/ml). Optimal cytoreduction was not achieved in order to preserve the patient's fertility and avoid adjacent organ injury. Residual tumor responded to adjuvant chemotherapy with a sharp decline in AFP levels, and confirmed remission was documented by serial (18)F-fluorodexyglucose-positoron emission tomography and computerized tomography (FDG-PET/CT). In cases of advanced YST with unresectable residual disease, AFP levels combined with FDG-PET/CT scans may be a helpful way to monitor treatment response and assist in treatment planning for a disease that primarily affects young women who may desire to preserve fertility.