Thymoma without Myasthenia Gravis Showing Size Fluctuation in Parallel to Alopecia Areata Activity: A Case Report

Thymomas are commonly associated with autoimmune diseases such as myasthenia gravis (MG), pure red cell aplasia, and hypogammaglobulinemia, while those associated solely with alopecia areata (AA) are extremely rare. A 55-year-old woman with AA underwent chest computed tomography, which revealed a 33-mm anterior mediastinal cystic mass with fluctuating size. She was referred to our department for evaluation of a suspected cystic thymoma. The patient underwent thoracoscopic tumor resection under general anesthesia with isolated lung ventilation in the left lateral decubitus position. The operation lasted 81 minutes with minimal blood loss, and her postoperative course was uneventful. Histopathology confirmed a type B2-dominant thymoma. Notably, the patient's AA improved rapidly after surgery and did not recur for at least 3 years. This case strongly suggests a potential immunological relationship between AA and thymoma, though further research is needed to confirm this relationship.