Chronic lymphocytic leukemia (B-cell) in the course of polycythemia vera. Description of a case with an unusual chromosomic anomaly.

The present paper describes the case of a patient who developed a B-cell chronic lymphocytic leukemia (B-CLL) 15 months after the diagnosis of polycythemia vera, which had been treated only with phlebotomies. In spite of lymphocytosis and the clinical signs and symptoms of leukemia, the patient exhibited at the same time presumptive elements of polycythemia (high LAP index levels, a high number of neutrophils). Cytogenetic investigations, carried out after the appearance of B-CLL, revealed the presence of an unusual abnormality (18 p+) both in bone marrow not stimulated by mitogens and in PWM-stimulated circulating lymphocytes. This case, which is the ninth of its kind described in the literature, offers some interesting observations about the association between myeloproliferative and lymphoproliferative syndromes.