This is a case report of a rare finding of an extragonadal yolk sac tumor in a 37-year-old patient who presented with shortness of breath and abdominal bloating. During imaging and staging surgery, the findings were strongly suggestive of an extragonadal advanced tumor presenting with peritoneal dissemination, predominantly affecting omentum, with no clear primary origin. Histology revealed an extragonadal yolk sac tumor in a pure form outside the ovaries. Lacking an obvious origin elsewhere, the tumor was highly suspected to have truly originated from the omentum. The patient underwent surgery and four cycles of chemotherapy consisting of cisplatin, etoposide, and bleomycin. One-year outpatient follow-up thereafter showed no relapse. We herein discuss a possible site of the tumor origin and its development, as well as diagnostic challenges and disease prognosis.
Keywords: biopsy; diagnostic imaging; endodermal sinus tumor; female; omentum; ovary; ultrasonography; yolk sac.