Thymoma associated with autoimmune diseases: 85 cases and literature review

To describe the clinical features, treatment, and outcome of autoimmune diseases (AD) in a cohort of patients with thymoma.

Pathological records from three university hospitals, between 2005 and 2011, were reviewed to identify patients with thymoma. Patients with thymoma and AD were compared with patients with thymoma without AD.

47/85 (55%) cases of thymoma had AD, including myasthenia gravis (MG) (n=33), Hashimoto's thyroiditis (n=4), Isaac's syndrome (n=3), Morvan syndrome (n=2), pure red cell aplasia (n=2), systemic lupus (n=2), lichen planus (n=2), and one case of each following conditions: aplastic anemia, autoimmune hemolytic anemia, Good's syndrome, pemphigus, autoimmune hepatitis, Graves' disease, limbic encephalitis, and inflammatory myopathy. Six patients (7%) presented at least 2 ADs. The median duration of follow-up after surgery was 60 months (40-78 months). In 32 patients, the diagnosis of AD preceded the diagnosis of thymoma, in 9 patients, thymoma was diagnosed at the same time as the AD and 7 patients had been operated on when they developed an AD. We found a significative difference on the Masaoka stage between the MG patients and the patients who present another AD (p=0.028). No risk factor for developing an AD after thymectomy was identified.

We describe here the long-term follow-up of a large series of AD related to thymoma. Our results confirm previous data concerning AD occurrence in patients with thymoma and suggest that preexisting autoimmunity is not a risk factor for developing autoimmune manifestations after thymectomy.