概述
Enchondroma is a benign indolent intramedullary hyaline cartilage neoplasm。Accounts for 10% of all benign osseous tumors。Limited growth, most lesions are less than 5 cm in maximal dimension。
一般没症状，除非发生病理性骨折。大约50%发生在手或足上，而这其中大部分发生在指/趾骨上。肱骨及股骨近端是最常见的长骨发病部位。中轴骨（骨盆、脊柱、肋骨）等不常见，但该部位的肿瘤常常具有恶性倾向（软骨肉瘤）。
分型
Solitary Enchondroma
Multiple Enchondromas (Enchondromatosis/Ollier's Disease)
Maffucci Syndrome (Multiple Enchondromas and Soft Tissue Hemangiomas)
影像学特征
髓腔内生软骨瘤表现为溶骨性。肿瘤上层皮质骨变薄，一旦出现病理性骨折，皮质骨仍保存完整，也不会出现软组织肿块。若皮质骨受到侵蚀或变厚，出现软组织团块，往往是内生软骨瘤恶变的征象。
组织学特征
内生软骨瘤由分化良好的透明软骨组成。长骨内生软骨瘤表现为软骨细胞减少和无细胞非典型增生，丰富的蓝染软骨样基质，很少能找到双核细胞。和内生软骨瘤相比，手足和骨膜等处的软骨瘤表现为细胞非典型增生，但仍不能诊断为恶性。在长骨的软骨瘤，基质粘液样改变高度提示恶变；但在手足的小块骨，小幅度基质粘液样变不能断定是软骨肉瘤。恶性肿瘤可以穿透骨小梁，良性肿瘤不会穿透骨小梁破坏皮质骨。
鉴别诊断
The main differential is with a low grade (Grade 1) chondrosarcoma
Can be very difficult to differentiate from a Grade 1 Chondrosarcoma from an enchondroma based on histology
It is easy to differentiate from a grade 2 or 3 chondrosarcoma by means of histology which are hypercellular, pleomorphic and demonstrate mitotic figures
Radiographs and clinical history are important for differentiation
Biopsies are not useful for differentiating an enchondroma from a low grade chondrosarcoma
Features consistent with chondrosarcoma
Pain attributable to lesion
Age greater than 50
Cortical destruction and a soft tissue mass
Periosteal reaction and thickening
Endosteal erosion>2/3 cortical thickness on a CT scan
Size greater than 5 cm
Bone Scan: Lesion that is hotter than ASIS
治疗
内生软骨瘤应行刮除术，必要时骨移植修复骨缺损。如果肿瘤生长活跃或患者感觉疼痛，活检和刮除术应同时应用。如果刮除干净，术后肿瘤复发率极低。因为肿瘤很少侵犯皮质骨，所以只需刮除肿瘤即可，有时手术边界可扩展到周围1~2mm皮质骨。
Enchondromas are benign, indolent (not growing) tumors
Indications for surgery:Digits: Impending or actual pathological fracture，Intralesional curettage and bone graft or cement；Long bones: Rare to fracturea，usually observe
If grows it is considered chondrosarcoma and would recommend surgery accordingly
预后
Recurrence rate following curettage is <5%。
Recurrence of an enchondroma suggests malignancy。
There are rare cases where enchondromas can dedifferentiate into a chondrosarcoma or dedifferentiated chondrosarcoma (low grade chondrosarcoma with an osteosarcoma, fibrosarcoma or malignant fibrous histiocytoma arising adjacent to it)。
参考文献：
1、http://www.tumorsurgery.org/
2、王正义 主编《足踝外科学》人民卫生出版社，2006年
