[Recurrent Thymoma Responding to Low-dose Corticosteroid Therapy:Report of a Case]

We report a rare case of recurrent thymoma that responded to low-dose corticosteroid therapy. A 54-year-old woman underwent extended thymectomy for invasive thymoma (World Health Organization classification type AB, Masaoka stage III). Despite multiple treatments, including radiotherapy, surgical resection of pleural dissemination, and chemotherapy with S-1 and carboplatin plus paclitaxel, the tumor showed progressive disease. At 71 years of age, low-dose prednisolone (5-20 mg/day) was incidentally administered for a dermatologic condition. Subsequently, marked tumor regression was observed on chest radiography without any additional anticancer treatment. Tumor control was maintained with 10 mg/day prednisolone. The patient later died of sepsis unrelated to thymoma progression. This case suggests that even low-dose corticosteroids may exert clinically significant antitumor effects in thymoma, particularly in refractory cases.