Concurrent thymoma, thymic carcinoma, and T lymphoblastic leukemia/lymphoma in an anterior mediastinal mass

We report a case of a 62-year-old man with concurrent thymoma, thymic carcinoma, and T lymphoblastic leukemia/lymphoma. Computed tomography revealed a 5.5-cm anterior mediastinal mass, and surgical resection was performed. Histologically, the mass showed concurrent thymoma (type AB), thymic carcinoma, and T lymphoblastic leukemia/lymphoma. Lymphoma cells infiltrated in the left lung, pulmonary hilar lymph nodes, and involved bone marrow. The patient underwent chemotherapy for T lymphoblastic leukemia/lymphoma and achieved remission. One year after surgery, he remains free of both thymoma and thymic carcinoma, and T lymphoblastic leukemia/lymphoma remains complete remission under maintenance therapy. Thymoma and T lymphoblastic leukemia/lymphoma can combine in the same mass, although this is quite rare. At the time of the diagnosis of thymoma, additional attention should be directed toward lymphocytes in the background.