Extragonadal Pelvic Yolk Sac Tumor in a Postpubertal Patient: Case Report With Radiologic Correlation and Review of the Literature

Yolk sac tumor, also referred to as endodermal sinus tumor, is an aggressive malignant germ cell neoplasm that most commonly originates in the gonad. Its occurrence in extra‐gonadal sites is infrequent and is highly malignant, with only a handful of cases reported in the literature. With the help of this article, we want to make readers aware of the rare site of yolk sac tumor, its clinical presentation, and its radiological findings. As clinicians, we should be vigilant to consider differential diagnoses for an underlying etiology, like yolk sac tumor, for a patient presenting with a subcutaneous lump. Even though swelling in subcutaneous regions, in most cases, represents a benign diagnosis, malignant ones should always be kept in the back of the mind while managing patients. Variation in the site of extragonadal germ cell tumors has been highlighted with this paper, and herein, we aim to make readers aware of a rare and uncommon germ cell tumor, acknowledging the importance of imaging findings in making a diagnosis and the approach for its management.