Myasthenia gravis: comparative evaluation of medical and surgical treatment.

Sixty-eight patients with myasthenia gravis were evaluated and compared to determine the results of medical and surgical treatment; eight patients with thymoma were evaluated separately. In the group of 30 non-thymoma patients treated medically 50% of patients derived moderate to good improvement over a mean follow-up period of 11 years. Ten per cent of patients in this group died from myasthenia.In the group of 30 non-thymoma patients treated by thymectomy, 83% achieved good to excellent improvement. There was no surgical or myasthenic mortality over a mean follow-up period of nine years.The results of treatment in the eight thymoma patients were decidedly inferior and there was no significant difference between the medically and surgically treated patients. Fifty per cent showed only moderate improvement during a mean follow-up of five years and 50%, after initial improvement, deteriorated later and died from myasthenia between three and four years after thymectomy.Two additional patients had thymoma without myasthenia. Neither of them had developed myasthenia, two years following thymectomy in one case and after 25 years in the other, despite recurrence of the tumour with extensive invasiveness in the very long-standing case.