骨母细胞瘤少见 ,多发生于脊柱和长管骨 ,发生在髌骨罕见。我院遇见 1例报告如下。患者　男 ,2 7岁 ,左膝疼痛 2月余 ,近日加重入院。检查 :左膝关节轻度肿胀 ,不红 ,有局部压痛。实验室检查均正常。Ｘ线检查 :正位片见左髌骨约有 2 .5ｃｍ× 3ｃｍ大小的膨胀性改变 ,外围可见 Osteoblastoma rare, mostly in the spine and long bones occur in the rare patella. I met a hospital report as follows. Male patient, 27 years old, left knee pain more than 2 months, recently increased admission. Check: mild swelling of the left knee, not red, there are local tenderness. Laboratory tests are normal. X-ray examination: the anteroposterior film see the left patella about 2. 5cm × 3cm size of the swelling of the changes in the periphery visible