In very rare cases, myasthenia gravis can present as a paraneoplastic syndrome, which means that an underlying cancer like bronchogenic carcinoma or thymic neoplasm (also known as thymoma) generates an immune response which results in generation of autoantibodies.

在极罕见的情况下，重症肌无力会表现出副肿瘤综合征，这意味着潜在的癌症如支气管肺癌、胸腺肿瘤导致免疫应答产生了自身抗体。