[Myelodysplastic syndrome associated with clonal proliferation of B lymphocytes].

We present an unusual case of the myelodysplastic syndrome (subtype refractory anemia with the excess of blasts in transformation--RAEB-t) associated with significant increase of IgG (4,700 mg/dl), lambda (160 U/dl) in blood serum and circulating clone of B lymphocytes SIgG, lambda, manifesting clonal rearrangement of JH domain. Peripheral blood cells of the patient showed two different chromosomal abnormalities: 47,XY, + del/8/p? and 47,XY, +22, +14, -19. We suppose that two independent neoplastic clones are developed in the described case, i.e. a population displaying markers of myeloblasts and monoblasts, and a clone of B lymphocytes.