Purpose: Thymolipomas are rare tumors of the anterior mediastinum accounting for up to 9% of all thymic tumors. These tumors are associated with autoimmune diseases in up to 50% of the patients, including myasthenia gravis, aplastic anemia, hypogammaglobulinemia, lichen planus, and Graves' disease. These tumors with a fatty appearance also can arise in older patients with autoimmune disease.
Methods: This retrospective study evaluated the thymolipomas from nine patients at a single institution, which were resected between 2002 and 2007. The clinical data as well as radiologic findings were evaluated, together with the follow-up.
Results: Seven patients initially presented with myasthenia gravis, and therefore they underwent a resection of the thymus, even though imaging techniques did not reveal a tumor in any of the cases. Another patient showed no symptoms of autoimmune disease for 20 years, and though cardiomegaly was suspected, further investigation revealed a thymolipoma. The symptoms of myasthenia gravis improved following the surgery in one patient. During follow-up, one patient died due to esophageal cancer, and the remaining patients are alive without recurrence.
Conclusions: Thymolipomas are benign tumors that show an excellent outcome. Patients with autoimmune disease symptoms occasionally show an improvement of the symptoms after a resection of the tumors.