患者男，７岁。发现右足背肿痛２个月，治疗无效而来就诊。查体：右足背外上隆起，质硬不活动，边界清，轻压痛，皮色正常，皮温不高。Ｘ线表现：右足第３跖骨基底及中段中心呈溶骨性多囊状透光区，内有粗的骨嵴分隔，病变长４８ｃｍ，最宽达１５ｃｍ，骨皮质膨胀变薄，其 Male patient, 7 years old. The right foot was found to have swelling and pain for 2 months and treatment was ineffective. Physical examination: The right foot is lifted up outside, hard and inactive, the border is clear, light tenderness, skin color is normal, skin temperature is not high. X-ray findings: The third basement of the right foot and the center of the middle part of the sacrum are osteolytic polysaccate translucent areas with a thick bone septum. The lesions are 4  8 cm in length, and the width is up to  5 cm. The cortical bone expands and thins. its