[Granulocyte abnormal chromatin clumping syndrome: report of a new case and review of the literature].

Abnormal chromatin clumping syndrome (ACCS) is a rare granulocyte disease halfway between Ph'-negative chronic myelogenous leukaemia (CML) and the myelodysplastic syndromes. A new case of such syndrome is presented, the patient being a 65 year-old man with anaemia, thrombocytopenia and myelaemic leucocytosis with abnormal condensation of the neutrophils' chromatin. Marked granulocytic hyperplasia was present in the bone marrow with strikingly dysplastic features, along with a decrease of the remaining blood cell lines. Irregular nuclear outlines and heterochromatin clumps separated by euchromatin bands were seen in the more mature granulocytes upon ultrastructural studies. No cytogenetic abnormalities were found in the bone marrow, and no ber-abl gene rearrangement was present in white cells from peripheral blood. The clinical course was marked by persistence of the anaemia and increasing leucocytosis which required 6-mercaptopurine treatment. Acute myeloblastic leukaemia occurred one year later and the patient died shortly after. It was concluded, from this case and others reported in the literature, that, with regard to its clinical course and proliferative character, ACCS is closer to Ph'-negative, bcr-abl negative CML rather than to the myelodysplastic syndromes.