Prolymphocytic leukaemia: surface morphology in 21 cases as seen by scanning electron microscopy and comparison with B-type CLL and CLL in 'prolymphocytoid' transformation

B-prolymphocytic leukemia: Is it time to retire this entity?

B-prolymphocytic leukemia (B-PLL) is included as a distinct entity in the current World Health Organization classification of hematolymphoid neoplasms. However, the diagnosis of B-PLL has presented several challenges since its conception, and over the past decades investigations of B-PLL have revealed substantial biologic and molecular heterogeneity. These data have shown that many B-PLL cases present many similarities with other types of small B-cell lymphomas, and that small B-cell lymphomas can undergo prolymphocytoid transformation. As a result, the frequency of B-PLL has markedly decreased, and currently B-PLL is a very rare entity. Most recent studies focused on B-PLL cases have been conducted on limited cohorts, precluding robust conclusions. In this article, we provide a concise historical review of B-PLL and describe the diagnostic and clinical challenges associated with establishing this diagnosis. We also argue that cases currently classified as B-PLL are unlikely to be a unique biologic entity, but rather represent a state of morphologic transformation characterized by many prolymphocytes that is shared by various types of small B-cell lymphoma.

Scanning electron microscopy of peripheral blood smears: comparison of normal blood with some common leukemias

Peripheral blood smears prepared routinely from nonneoplastic and leukemia cases were studied using the scanning electron microscope (SEM). The peripheral blood glass slide is examined directly in the SEM following application of a thin carbon coat. The morphology of the nonneoplastic and neoplastic smears is described in detail utilizing the SEM secondary electron detector and backscattered electron detectors. Certain cell features are measured as well with the use of the measuring software resident in the SEM. The appearance of the SEM images of peripheral smear slides is compared to that of slides from fixed, processed, and sectioned bone marrow cases previously reported. The problem of cell constituent loss and overall shrinkage in the routinely processed and sectioned material is noted. The lack of these problems in the peripheral blood smear slides and their better appearance is emphasized. The resemblance of neoplastic cells to their normal counterparts is discussed. The monoblast resembles the normal monocyte but both cell size and nuclear size are greater; the moderately reticulated nuclear chromatin distinguishes the monoblast. Neoplastic lymphoid cells maintain the wispy extensions of the cytoplasm perimeter resembling microvilli and thereby differ from myeloid and monocytic cells. The neoplastic lymphoid cell shows coarse clumping of nuclear chromatin and in some instances coarse chromatin anastomoses to distinguish it from the normal lymphocyte. Lymphoid cells of acute lymphoblastic leukemia are 33% larger than those of chronic lymphocytic leukemia and normal lymphocytes. The neoplastic myeloblast has a finely granular nuclear chromatin, maintains a smooth cytoplasmic perimeter, and may show cytoplasmic reticulations. The myeloblast differs from the lymphoblast in that the former has a smooth cytoplasm perimeter. Further, myeloblasts show nuclear lobulations more frequently than lymphoblasts. Comparison of SEM findings with the three case studies by flow cytometry indicates satisfactory correlation. In case 15, flow cytometry indicated a monocyte subset positive for CD14 and CD64 among the neoplastic myeloid forms. A candidate for such a cell is recognized morphologically as well. The availability for SEM ultrastructural study of all the cells, both neoplastic and nonneoplastic, on a routine diagnostic smear slide is emphasized.

Hairy cell leukaemia: effects of phorbol ester on cell morphology and adherence and comparison with other B-cell neoplasias

This report documents phorbol ester-induced changes in cell morphology in 9 patients with hairy cell leukaemia (HCL) and contrasts them with those obtained in cells from 20 patients with B-type chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma in leukaemic phase (NHL). The phorbol ester caused hairy cells to adhere strongly and produce thin elongated cytoplasmic extensions. Other cells showed marked surface ruffling, and contained increased numbers of phagolysosomes, although cells still retained ribosomal lamellar complexes. This in vitro growth pattern differed from that observed in B-CLL and NHL cells, which readily detached in clumps with minimal adherence. CLL and NHL-cells did not show macrophage features but developed plasmacytoid and hairy cell-like features. It is suggested that these different growth patterns may aid in distinguishing HCL from other B-cell neoplasias.