软骨母细胞瘤为一种少见的起源于软骨的良性骨肿瘤,占所有原发性骨肿瘤的1％弱,主要发生于青年,约65％患者的年龄为20岁左右。男女发病比例为2:1～3:1,最常见的发病部位是长管状骨的骨骺,特别是肱骨近端、胫骨近端和股骨远端,该肿瘤亦可发生于扁平骨,仅2.9～8.8％生长在骨盆,而Y形软骨则是骨盆软骨母细胞瘤最常见的发病部位。作者报告了2例生长在Y形软骨的具有侵袭性X线所见的软骨母细胞瘤,其X线平片表现为:病变区溶骨性破坏,皮质膨胀,未见骨化及钙化。CT检查并示溶骨性破坏区内有点状钙化,软骨下受累及盆腔内软组织肿块。活检结果发现边界清楚的小多边形细胞增殖及稀疏的破骨型巨细胞。作者指出,该病X线上大多表现为侵袭性甚至发生恶性变的原因为:①肿瘤位置很深,以致需较长时间才能 Chondroblastoma is a rare, benign bone tumor of cartilage originating from 1% of all primary bone tumors. It occurs mainly in young people, and about 65% of patients are about 20 years old. The ratio of males to females is 2:1 to 3:1. The most common site of disease is the osteophytes of long tubular bones, especially the proximal humerus, the proximal humerus, and the distal femur. The tumor can also occur in flat bones, only 2.9- 8.8% grew in the pelvis, and Y-shaped cartilage was the most common site of pelvic chondroblastoma. The authors reported 2 cases of chondroblastoma with invasive X-rays on Y-shaped cartilage. The X-ray findings showed: osteolytic destruction of the lesion area, cortical swelling, and no ossification and calcification. CT examination showed that there was a bit like calcification in the osteolytic destruction zone, subchondral involvement and pelvic soft tissue mass. Biopsy results revealed well-defined small polygonal cell proliferation and sparse osteoclasts. The authors pointed out that most of the X-ray manifestations of the disease are invasive or even malignant. The reasons are as follows: 1 The tumor is located so deep that it takes a long time