Leukemic (or stage V) lymphosarcoma.

We have studied 24 cases of secondarily leukemic (stage V) lymphosarcoma (LS), 31 cases of "d'emblée" leukemic LS, and ten cases of lymphoid leukemic neoplasias transitional between "d'emblée" leukemic LS and chronic lymphocytic leukemia (CLL). These cases only concern the common types of the WHO classification of LS, i.e., the prolymphocytic, the lymhoblastic, and the immunoblastic. Some cases have also been classified by cell surface markers. The secondarily leukemic conversion occurred in 40% of the lymphoblastic types, in 14% of the prolymphocytic types, and in 17% of the immunoblastic types. It never occurred at stage I but could occur after any other stage. The mediastinal involvement was observed in three types, but most often in the lymphoblastic type. The prognosis after an acute lymphoid leukemia (ALL) treatment comprising active immunotherapy following chemo(radio)therapy is better for the leukemic prolymphocytic and lymphoblastic LS than for the immunoblastic type. Two patients (one of the lymphoblastic type) are in complete remission after 8 and 5 years, respectively. We have described ten cases of "d'emblée" leukemic LS with either large lymphoid or extra-lymphoid masses, bone marrow leukemic cell involvement, and LS aspects of neoplastic cells. Mediastinal abdominal, or other tumor masses are frequent. The prognosis for "d'emblée" leukemic LS following an ALL treatment is less favorable than ALL prognosis for patients of all ages including children. However, the first remission curve breaks at the 18th month and may form a plateau for about 30% of the patients of all ages. One patient has been in remission for more than 8 years after immunotherapy. We have also described ten cases of lymphoid neoplasia, whose cells cytologically and by the intensity of Ig secretion resemble leukemic prolymphocytic LS cells. However, the disease is more sensitive to CLL treatment than to LS or ALL treatment. Hence, there may be transitional conditions between leukemic LS and CLL. Finally, we have discussed the different possible frontiers between nonleukemic and leukemic LS and proposed two tests to detect the leukemic stage early: the systematic search for LS cells in the peripheral blood after concentration of nucleated cells by centrifugation and for cells carrying immune markers in the isolated mononuclear cell population of peripheral blood and the bone marrow.