Abstract
We report a case of thymoma that showed repeated growth and regression within a short period of time. A 28-year-old man visited our hospital with fever and chest pain. A heterogeneous 35-mm shadow was detected in the anterior mediastinum on computed tomography (CT), and the inflammatory response was elevated. Symptoms and inflammation improved without treatment, and the mass regressed in size to 29 mm on CT performed 1 month later. After another 3 months, the patient visited our hospital again for fever and chest pain. The mass had grown to 48 mm, and the inflammatory response was again elevated. Symptoms and inflammation improved without treatment, and the mass had regressed to 25 mm on CT performed 2 months later. Nonetheless, surgery was carried out due to the suspicion of a mediastinal tumor. The histological diagnosis was thymoma. Intratumoral hemorrhage, fibrosis, and a mixture of old and new inflammation were also observed, consistent with the history of repeated growth and regression. Although spontaneous regression of thymoma is occasionally reported in Japan, a case of two repetitions of growth and regression in a short period is extremely rare. This case of a rare thymoma is reported herein.
