Triad of lichen planus, myasthenia gravis, and thymoma.

Myasthenia gravis in a woman was followed by the development of severe erosive lichen planus and thymoma. Lichen planus is not ordinarily associated with other cutaneous or systemic disorders. The reported immunologic findings in some patients with lichen planus and especially the occasional association of lichen planus with certain disorders linked with immunologic disturbances suggest an autoimmune pathogenesis for this disorder.