骨盆软骨肉瘤影像特征及其病理基础

Analysis of radiological features relative to pathology in pelvic chondrosarcoma

目的分析骨盆软骨肉瘤的影像表现及其病理基础，以提高诊断准确性。方法回顾分析经手术病理证实的骨盆软骨肉瘤12例，术前分别经X线平片、CT平扫、MR SE T1WI、T2WI和增强T1WI，仔细复习影像学扫描结果并和手术病理作对照。结果12例骨盆软骨肉瘤，普通型11例，去分化型1例。发病部位包括髂骨2例，髋臼3例，坐骨和耻骨6例，骶尾骨1例。肿瘤直径4．7～17．0cm，〈5．0cm者1例，5．0～10．0em者6例，〉10．0cm者5例。病灶呈轻度膨胀性或溶骨性骨质破坏，11例边缘呈扇贝状分叶，1例境界不清。X线平片检查8例中，弓环状钙化1例，隐约钙化6例，无钙化1例，显著软组织肿块3例，骨膜增生1例。CT检查5例，肿瘤密度等于或低于肌肉密度，5例均可见轻度弓环状钙化和软组织肿块。MR检查7例，T1WI等低信号7例，T2WI显著高信号7例，其中6例T2WI高信号内可见弓环状低信号分隔，1例见低信号结节，7例见明显软组织肿块。增强T1WI6例，所有小叶分隔呈进行性持续强化，小叶自身不强化。结论MRI可直接显示骨盆软骨肉瘤的病理特征，优于CT和平片。CT对显示解剖学复杂的骨盆病灶及轻微钙化等有明显价值。

Objective To Explore the imaging features relative to pathology of pelvic chondrosarcoma and to evaluate the clinical value. Methods All 12 cases patients with primary pelvic chondrosarcoma confirmed by pathological examination underwent radiography, spiral CT plain scanning, MR SE-T1WI, FSE-T2WI and SE-T1WI enhancement scanning before operation. The imaging data was reviewed and analyzed retrospectively to compare with surgical and pathological results. Results Eleven conventional chondrosarcoma and one dedifferentiated chondrosarcoma were located in different parts of pelvis. The diameters of the tumors ranged from 4. 7 to 17. 0 cm with one case less than 5.0 cm, 6 cases being 5.0--10. 0 cm and 5 cases more than 10. 0 cm. The CT value of 5 cases was identical or inferior to muscle with mild to moderate ＂ring-and-arc＂ mineralization and soft mass. MR imaging depict the high water content of these lesions as very high signal intensity was detected on T2WI. Six cases showed typical ＂ring- and-arc＂ fibrous tissue which enhanced persistently. Aggressive features of deep endosteal scalloping and soft-tissue extension was also found in these cases. Conclusions Radiographic findings can suggest the diagnosis of pelvic chondrosarcoma when there is typical ＂ ring-and-arc＂ fibrous tissue, mineralization, aggressive features of deep endosteal scalloping and large soft-tissue extension. MR imaging reflect directly this pathologic structure, superior to that of CT and radiography. CT is optimal to detect the matrix mineralization, particularly when it is subtle or when the lesion is located in anatomically complex pelvic areas.