1　病例报告患者男 ,13岁。因双下肢骨痛 2个月余 ,贫血 1周 ,于1999年 2月 2日入院。 2个月前 ,无明显诱因感双下肢骨痛、乏力。查体 :贫血貌 ,皮肤、粘膜无黄染、出血点 ,未见皮疹 ,颌下可触及肿大淋巴结 ,双下肢轻度凹陷性水肿 ,胸骨无压痛。实验室检查 :血红蛋白 6 7ｇ/Ｌ 1 Case report Male patient, 13 years old. Due to bone pain in both lower extremities for more than 2 months, one week of anemia was admitted to hospital on February 2, 1999. Two months ago, there was no obvious incentive to feel lower limb pain and fatigue. Physical examination: anemia appearance, skin, mucous membrane without yellow, bleeding, no rash, submandibular lymph nodes can be reached, mild depression in both lower extremities edema, no tenderness of the sternum. Laboratory examination : Hemoglobin 6 7g/L