Steroid-induced regression of malignant thoracic lymphoma

Spontaneous or steroid-induced regression of malignant lymphoma has been occasionally reported in the literature. To the best of our knowledge, the rapid and dramatic regression of malignant thoracic lymphoma with steroid therapy only has not been reported yet. In this report, we describe a case of malignant thoracic lymphoma that initially manifested as a huge anterior mediastinal mass, and then it drastically regressed within 4 days in response to steroid therapy. Because of the changing histological features, the correct diagnosis was finally made 5 months later. So radiologists should recognize the possibility of steroid-induced regression of malignant thoracic lymphoma in a short period of time in addition to the spontaneous regression of lymphomas. Although there is no pathologic evidence suggesting the recurrence of lymphoma, close radiographic follow-up is mandatory and the clinician should be given a warning about the possibility of recurrence of malignant lymphoma if imaging features are compatible with recurrence of lymphoma.