卵黄囊癌是发生于生殖腺和生殖腺外的一种罕见的恶性生殖细胞肿瘤。其中原发于腺外者更为罕见。有文献记载的腺外原发部位有:骶尾部、骨盆、阴唇、阴道、宫颈、阔韧带、前列腺、腹膜后、纵隔、肝脏、胃、上颌窦、硬腭、颅内、垂体和松果体。而本例原发于牙龈部位的卵黄囊癌,到目前为止文献中未见报道。 Yolk sac cancer is a rare malignant germ cell tumor that occurs outside the gonads and gonads. Among them, the origin in the gland is more rare. There are documented primary parts of the gland outside the sacrococcygeal, pelvis, labia, vagina, cervix, broad ligament, prostate, retroperitoneal, mediastinal, liver, stomach, maxillary sinus, hard palate, intracranial, pituitary and pineal. In this case, primary yolk sac cancer in the gum area has not been reported in the literature so far.