Woertler K, Lindner N, Gosheger G, Brinkschmidt C, Heindel W
Department of Clinical Radiology, Westfalian Wilhelms University of Muenster, Germany.
Eur Radiol. 2000;10(5):832-40. doi: 10.1007/s003300051014.
Osteochondromas can be complicated by mechanical irritation, compression or injury of adjacent structures, fracture, malignant transformation, and postoperative recurrence. Magnetic resonance imaging represents the most valuable imaging modality in symptomatic cases, because it can demonstrate typical features of associated soft tissue pathology, which can be differentiated from malignant transformation. Reactive bursae formation presents as an overlying fluid collection with peripheral contrast enhancement. Dislocation, deformation, and signal alterations of adjacent soft tissue structures can be observed in different impingement syndromes caused by osteochondromas. Magnetic resonance imaging provides excellent demonstration of arterial and venous compromise and represents the method of choice in cases with compression of spinal cord, nerve roots, or peripheral nerves, depicting changes in size, position, and signal intensity of the affected neural structures. Malignant transformation as the most worrisome complication occurs in approximately 1% of solitary and 5-25% of multiple osteochondromas. Magnetic resonance imaging is the most accurate method in measuring cartilage cap thickness, which represents an important criterion for differentiation of osteochondromas and exostotic (low-grade) chondrosarcomas. Cartilage cap thickness exceeding 2 cm in adults and 3 cm in children should raise the suspicion for malignant transformation. Finally, MR imaging can detect postoperative recurrence by depiction of a recurrent mass presenting typical morphological features of a cartilage-forming lesion.
骨软骨瘤可并发对相邻结构的机械性刺激、压迫或损伤、骨折、恶变以及术后复发。磁共振成像（MRI）是有症状病例中最有价值的影像学检查方法，因为它能显示相关软组织病变的典型特征，从而可与恶变相鉴别。反应性滑囊形成表现为覆盖的液体积聚，周边有对比剂强化。在骨软骨瘤引起的不同撞击综合征中，可观察到相邻软组织结构的脱位、变形及信号改变。MRI能很好地显示动静脉受压情况，是脊髓、神经根或周围神经受压病例的首选检查方法，可描绘受影响神经结构的大小、位置及信号强度变化。恶变是最令人担忧的并发症，约1%的孤立性骨软骨瘤和5% - 25%的多发性骨软骨瘤会发生恶变。MRI是测量软骨帽厚度最准确的方法，软骨帽厚度是鉴别骨软骨瘤和外生性（低度）软骨肉瘤的重要标准。成人软骨帽厚度超过2 cm、儿童超过3 cm应怀疑恶变。最后，MRI可通过显示具有软骨形成性病变典型形态特征的复发肿块来检测术后复发。
