骨母细胞瘤和成骨肉瘤易于区别,但是当骨母细胞瘤有轻度至中度不典型性或成骨肉瘤仅有轻度异形性特,则鉴别诊断困难。我们曾遇到误诊骨母细胞瘤和成骨肉瘤各一例。 例一、男,22岁,1971年7月无任何诱因出现左下肢疼痛,10月左膝屈伸障碍,患肢肌肉萎缩,但无局部红肿热。12月31日入院,检查见左下肢肌肉明显萎缩,左膝只能屈90度,伸160度。X线检查,左股 Osteoblastic tumors and osteogenic sarcomas are easily distinguished, but differential diagnoses are difficult when osteoblastomas have mild to moderate atypicalities or osteogenic sarcomas have only mildly abnormalities. We have encountered one case of misdiagnosis of osteoblastoma and osteosarcoma. Case 1, male, 22 years old, in July 1971 without any incentive to appear left lower limb pain, left knee flexion and extension in October, limb muscle atrophy, but no local swelling. Admitted to hospital on December 31, the examination showed that the muscles of the left lower extremity had shrunk. The left knee could only flex 90 degrees and stretched 160 degrees. X-ray examination, left strand