Endodermal sinus tumor (yolk-sac carcinoma) of the orbit

A 15-month-old boy with rapidly progressive proptosis had an unusual malignant germ-cell tumor of the orbit and nasopharynx identified as an endodermal sinus tumor (yolk-sac carcinoma). Endodermal sinus tumors arising in extra gonadal locations are highly malignant and generally lethal. The boy was treated with radiation and three-drug chemotherapy and has survived more than eight years.