Here are some of the points that will be against osteofibrous dysplasia: [骨髓腔内], [近卵圆形肿物]，体积：[1.8×1.5×1.2厘米]. Osteofibrous dysplasia should be in the cortex, usually extensive, and with distortion and deformity of the cortex.

But anyway, we all agreed that it is benign. :-)

骨纤维异常增殖症

I would think this is a benign tumor, most likely chondromyxoid fibroma. One can appreciate the vague lobular pattern under low power (slides 1, 2, and 7), with hypocellularity in the lobules and relatively hypercellularity in between the lobules. The patient age, tumor location radiation image, and gross appearance match with this entity pretty well.

很可能是：骨性纤维结构不良 (Osteofibrous dysplasia)。

但要与：

1.软骨黏液样纤维瘤 (Chondromyxiod fibroma)及

2.骨软骨黏液瘤 (Osteochondromyxoma)等相鉴别；

由于部分区域细胞丰富且胶原化，还要想到：

3.（骨的）促结缔组织增生性纤维瘤 (Desmoplastic fibroma of bone)。

但特殊的生长部位【胫骨】、漫长的病程【10年】及宽硕的、成熟趋势的【具有黏合线，即Paget现象】以及被覆肥大骨母细胞的小梁，暂且认为是骨性纤维结构不良 (Osteofibrous dysplasia)。尚需影像学进一步支持， X线更具特点。

谢谢评论。良性是肯定的。X线可能更能明确诊断。