Chronic granulocytic leukemia: the devastating consequences of genetic instability

Centroblastic transformation of chronic lymphocytic leukaemia with primary skin involvement--cutaneous presentation of Richter's syndrome

The development of a large-cell non-Hodgkin's lymphoma in a patient suffering from chronic lymphocytic leukaemia is known as Richter's syndrome, representing one of the possible anaplastic transformations of the leukaemia. Cutaneous involvement is an extremely rare event. The case of a 45-year-old man with B-cell chronic lymphocytic leukaemia is reported. Five years later multiple cutaneous nodules developed on his extremities. Biopsies of the skin showed a diffuse large-cell lymphoma, bearing the same cell surface immunoglobulin light chain isotype as the leukaemia, suggesting the original relationship between both neoplasms.

Application of the avidin-biotin-peroxidase complex technique for ultraimmunocytochemical characterization of leukemic cells

For simultaneous demonstration of cellular ultrastructure, myeloperoxidase activity, and presence of a membrane-bound antigen in a given blood cell, we examined three different fixatives: periodate-lysine-paraformaldehyde (PLP) and paraformaldehyde and glutaraldehyde for their applicability to preembedding electron microscopic immunocytochemistry using monoclonal antibodies and the avidin-biotin-peroxidase complex (ABC) technique. This procedure was examined in samples from 3 normal volunteers and 29 patients with acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), lymphosarcoma cell leukemia (LSCL), blastic phase of chronic myelogenous leukemia (CML-BC), or other unclassified leukemias. PLP fixation preserved the immunoreactivity of surface glycoproteins as well as immunoglobulins to the most satisfactory extent. Leukemic cells fixed with PLP maintained their fine structural details, so that we could identify their cytoplasmic organelles, although glutaraldehyde produced the best preservation of cellular ultrastructure. In three patients with ALL, our method revealed that a significant portion of blasts possessed both lymphoid surface antigens and peroxidase-positive cytoplasmic granules. Our method was also useful in identifying the lineage of peroxidase-negative leukemic cells, including monoblastic leukemia and megakaryoblastic leukemia cells. Ultraimmunocytochemistry using PLP fixation and the ABC technique may be a promising strategy for determining the nature of blastic cells that remain unclear after a conventional work-up, for characterizing leukemic cells in patients with a relatively low blast cell count in the bone marrow or peripheral blood, and for estimating the presence and frequency of leukemia with multilineage expression.