A Thymoma (aiienoma of T H E Thymus) from an Unusual Case O F Myasthenia Gravis, with Observations on T H E General Pathology1

In 1936 I presented a report of four cases of myasthenia gravis, in two of which gross thymic lesions were found. At that time in a review of the literature only 80 cases of myasthenia gravis which had come to autopsy were found, and among these were 35 in which a lesion of the thymus constituted a prominent anatomic feature. I t appears that progress toward a more exact understanding of myasthenia gravis has been largely hindered because of the small number of cases that have been studied by the pathologist. The importance of having recorded all cases of myasthenia gravis with definite pathologic findings I have previously emphasized. During the past year another case, which will be described here, came to my attention. Moreover, there was found a case reported by Lowenthal which had escaped notice and failed of inclusion in the tabulation in the earlier study; this case also is briefly summarized below. The addition of these 2 cases to those previously tabulated increases the total to 37 instances of thymic lesions in reported autopsied cases of myasthenia gravis.