OBJECTIVETo investigate the clinical significance of the serum anti-titin, anti-ryanodine receptor (RyR) antibody level and thymus CT scan in the diagnosis of myasthenia gravis with thymoma.

METHODSTotally 32 patients with myasthenia gravis who had received thymectomy were included in the study. Abnormalities were shown under CT scan of thymus in all these patients. The relationships were studied among the pathological diagnosis, CT findings, and serum level of thymoma associated antibodies: anti-titin and anti-RyR antibodies.

RESULTSThe pathological diagnosis of thymoma was made in 21 patients and thymus hyperplasia in 11 patients after operation. The sensitivity of CT scan in the diagnosis of thymomas was 90.5%, the specificity of serum thymoma associated antibodies in the diagnosis of thymoma was 100%.

CONCLUSIONThe thymoma-associated antibodies test is helpful in the differential diagnosis of thymomas and thymus hyperplasia; when combined with CT scan, it may achieve high sensitivity in the diagnosis of the thymoma.