Myasthenia gravis and alopecia areata.

Of 202 patients with myasthenia gravis (MG), 6 (3%) developed alopecia areata. All six patients had a thymoma verified by pathology; the frequency of alopecia areata rose to 17% of 35 MG patients with a thymoma. In one patient who had no recognizable tumor in the mediastinum, an ectopic thymoma was present in the anterior neck.