Thymoma-associated myasthenia gravis without acetylcholine receptor antibodies.

Patients with myasthenia gravis and thymoma usually present antibodies to the acetylcholine receptor (AchR-Ab). Only two cases of thymoma-associated myasthenia gravis without AchR-Ab have been previously reported. We describe a case of seronegative thymoma-associated myasthenia gravis as a further evidence of the variability of myasthenia gravis in terms of antibody profile and thymic pathological findings.