重症肌无力(MG)伴胸腺瘤者占全部MG 的10—15%,其中有家族史者约占2～3%。家族中有同患胸腺瘤者极少报道,但从未见有家族性胸腺瘤伴MG者,本文报道兄弟两人同患家族性胸腺瘤和MG。例1,31岁,渐进性咀嚼、吞咽困难、返流,复视伴肢体无力2个月,腾喜龙证实诊断,毗啶斯的明治疗有轻度改善。病后六个月时始用强的松,隔日80mg,两周内有显效。实验室检查:神经传导速度正常,肢体远端肌肉对重复电刺激无衰减现象, Myasthenia gravis (MG) with thymoma accounted for 10-15% of all MG, including family history of about 2 to 3%. Family with thymoma rarely reported, but never seen with familial thymoma with MG, this article reported two brothers with familial thymoma and MG. Example 1, 31 years old, progressive chewing, swallowing difficulties, reflux, diplopia with limb weakness 2 months, Teng Sik Lung confirmed the diagnosis, Minnesota mild treatment with mild improvement. Six months after the onset of prednisone, the next day 80mg, two weeks have markedly effective. Laboratory tests: normal nerve conduction velocity, limb distal muscles without repeated attenuation of electrical stimulation,