[Clinical characteristics and outcome of myasthenia gravis with and without thymoma after operation]

To explore the clinical characteristics and outcome of myasthenia gravis with and without thymoma after operation.

Two hundred and forty-three patients with myasthenia gravis surgically treated in our department from 1978 to 2003 were studied retrospectively. The clinical characteristics, complication, remission and survival were compared between myasthenia gravis with and without thymoma.

The patients of myasthenia gravis with thymoma were significantly older (t = 6.138, P = 0.000), had shorter duration of symptom (t = 3.783, P = 0.000), and also had higher myasthenia crisis rates after operation (chi(2) = 64.77, P = 0.000) than those of myasthenia gravis without thymoma. No differences of Osserman classification was found between the two groups (chi(2) = 7.678, P = 0.104). The complete remission rates and partial remission rates of myasthenia gravis with thymoma were significantly lower than those of myasthenia gravis without thymoma at 1 and 3 years (P = 0.049, P = 0.000; P = 0.015, P = 0.010), but no differences at 5 year (P = 0.457; P = 0.699). The survival rates of MG with thymoma were lower than that of MG without thymoma (Log-rank = 18.58, P = 0.000).

The clinical characteristics are different between myasthenia gravis with and without thymoma. The remission of symptom of myasthenia gravis with thymoma is worse than that of myasthenia gravis without thymoma in the near future, but is similar in the long future. The death rates of MG with thymoma is significantly higher than that of MG without thymoma.