患者女，５岁。发现骶部肿物２月余，因肿物生长快伴大便困难而入院。体检：一般情况尚可，全身表浅淋巴结无肿大，心、肺、肝及脾无异常。骶部有一半球形肿物隆起，如鸭蛋大，无压疼，不活动，质稍硬。肛诊触及肿物压迫直肠。其它部位无异常。Ｘ线片示骶骨无破坏；实验室血液 Female patient, 5 years old. It was found that more than two months later, an axillary mass was admitted to the hospital due to rapid growth of the mass and difficulty in defecate. Physical examination: The general condition is acceptable. There is no enlargement of the superficial lymph nodes, and there are no abnormalities in the heart, lung, liver and spleen. There is a hemispherical mass swelling in the ankle, such as large duck eggs, no pressure, inactivity, and a slightly harder mass. The anal diagnosis touches the tumor and compresses the rectum. No abnormalities in other parts. X-ray film showing no damage to the sacrum; laboratory blood