Yolk sac tumour involving floor of mouth: case report.

Yolk sac tumour is a rare malignant tumour of germ cell origin that usually arises from the gonads. It is extremely rare in the head and neck. We present a case of a yolk sac tumour that involved the floor of the mouth in a 14-month-old Chinese girl. The diagnosis was confirmed by histological examination that showed characteristic Schiller-Duval bodies, and immunohistochemical examination that showed α-fetoprotein being expressed within the cytoplasm of the neoplastic cells. The patient died 4 months postoperatively. To our knowledge, this is the first case of a yolk sac tumour of the floor of mouth that has been reported in an English journal.