Isolated marrow lymphoma: an entity of possible T-cell derivation.

Seven adults had a distinct clinicopathologic type of lymphoproliferative disorder of the bone marrow. All patients presented with weakness and pancytopenia; no evidence of gross extramedullary involvement was found. In 5 cases severe and prolonged bone marrow hypoplasia was associated with combination chemotherapy; 1 patient died of infection during initial therapy. In 6 of the 7 cases, clinical improvement occurred following therapy. As a terminal event, 2 patients developed a leukemic phase. Tumor cell from 4 patients were studied immunologically, and in 2 patients surface marker characteristics suggestive of T-cell tumor origin were found. In 2 cases, ultrastructural studies of lymphoid cells were compatible with a T-cell neoplasm. The above data suggest that these cases represent a distinct type of chemotherapy-sensitive lymphoma in which conservative initial treatment may induce a response without prolonged bone marrow hypoplasia.