T-cell lymphoblastic lymphoma with subsequent acute nonlymphocytic leukemia: a case report.

A case of T-cell lymphoblastic lymphoma is described in which the patient presented with a characteristic mediastinal mass and lack of bone marrow involvement. Immunologic studies of the surface phenotype of the malignant cells in a pleural effusion with monoclonal antibodies revealed the cells to be of thymic origin and distinguished them from the surface phenotypes seen in T-cell acute lymphoblastic leukemia. Twenty-five months after presentation with lymphoma, the patient developed an acute nonlymphocytic leukemia. With the improved prognosis seen in lymphoblastic lymphoma with intensive combination chemotherapy, it is expected that more cases of subsequent acute nonlymphocytic leukemia will be seen. In view of the natural history of lymphoblastic lymphoma to develop into lymphoblastic leukemia, it is important to be alert to a complicating nonlymphocytic leukemia.