Splenic irradiation for prolymphocytic leukemia: is it preferable as an initial treatment or not?

We describe a case of B-cell prolymphocytic leukemia (PLL) successfully treated with splenic irradiation (SI). A 69-year-old woman was admitted to our hospital because of massive splenomegaly and leukocytosis. Peripheral blood showed hemoglobin (Hb) 7.4 g/dl, platelets 48 x 10(9)/l and white blood cells (WBC) 50.3 x 10(9)/l with 90% prolymphocytes. Bone marrow was hypercellular with 60% prolymphocytes. Surface marker analysis revealed that prolymphocytes were positive for CD20, CD22, FMC7, HLA-DR and surface immunoglobulin (mu, delta and lambda), but negative for CD5 and mouse erythrocyte rosette. A diagnosis of B-cell PLL was made. SI (1.5 Gy x 4/week, total dose 19.5 Gy) was chosen for the treatment and a remarkable response was achieved immediately after the first irradiation. Finally, a single course of SI induced complete remission without any significant side effect. One year after the SI, she showed no splenomegaly and almost normal peripheral blood cell count (Hb 11.2 g/dl, platelets 100 x 10(9)/l, WBC 3.6 x 10(9)/l with 71% neutrophils and no prolymphocyte). She has been well for more than 24 months. This case showed that SI may remain valuable for an initial course of PLL treatment.