The syndrome of abnormal chromatin clumping in leukocytes.

A65-year-old female was admitted to our Institute for anemia-related symptoms. The hematological findings were as follows: Hb 65 g/L, platelet count 45310/L; WBC 18310/L with neutrophils 74%, lymphocytes 8%; monocytes 2%, promyelocytes 2%, myelocytes 12%, metamyelocytes 2%. When observed under the microscope, neutrophils were characterized by loss of segmentation (pelgeroid features) and abnormal chromatin condensation. Myeloperoxidase and PAS stainings were normally positive, and a high score of LAP was registered. Bone marrow smears were hypercellular, with excess blasts (13%) and an increase in myelocytes. The abnormal chromatin condensation was observed in mature myeloid forms (Figure 1). In addition, dyserythropoiesis and dysmegakaryopoiesis were observed. A bone marrow biopsy was not available. Karyotype analysis (kindly provided by Dr. Paolo Simi, Chief, U.O. Citogenetica, Azienda Ospedaliera Pisana) excluded the presence of Ph1 chromosome, and the BCR-ABL fusion gene was absent as well. Electron microscopy studies on peripheral blood cells were carried out, and the ultrastructural study