[Plasma cell leukemia. Study of 6 patients]

To analyse the clinico-biological characteristics, the clinical course and the response to therapy in a group of patients with plasma cell leukaemia (PCL).

Out of a total number of 107 patients diagnosed of multiple myeloma (MM) between 1983 and 1991, 6 were found to meet the criteria for PCL (prevalence: 5.6%). This was primary in 2 cases and secondary in the remaining 4. The M/F ratio was 2/1 and the median age was 63 years (range: 57-69 years).

Two patients had bone pain and two others weight loss at the onset of PCL. The outstanding haematological findings were increased ESR, normocytic-normochromic anaemia and thrombocytopenia, which were present in all cases. The percentage of peripheral blood plasma cells was between 29 and 70, and the bone marrow aspirate showed plasma cell infiltration over 40% in all cases. Serum M component was found in 5 patients, with decreased values of the polyclonal immunoglobulins; the remaining patient had non-secretory MM. Renal insufficiency was present in 3 patients at diagnosis. Three of the 4 patients with secondary PCL had been previously given combination chemotherapy and the remainder had received melphalan and prednisone. The period between the diagnosis of MM and the development of PCL ranged between 1 and 21 months (median 15 months). Three patients were treated with the M-2 protocol and the others received only supportive therapy. Transient partial response could be achieved in only one case with chemotherapy. All the patients have died, the actuarial survival median being 1 month (range, 1-7 months). Three patients died of infection, 2 of renal insufficiency and one of heart failure after acute myocardial infarction.

The poor prognosis of PCL was confirmed, along with the scarce response to therapy of these patients.