1/8. mastocytosis cells bearing a c-kit activating point mutation are characterized by hypersensitivity to stem cell factor and increased apoptosis.mastocytosis is characterized by abnormal infiltration of mast cells into various organs. An activating mutation in c-kit, involving an A --> T substitution at nucleotide 2648 has recently been described in some patients with mastocytosis. We describe a 12-year-old girl with this mutation in her bone marrow cells at diagnosis with a myelodysplastic syndrome (MDS) without evidence of mastocytosis, and then in peripheral blood mononuclear cells 1 year later after the emergence of mastocytosis. The role of the c-Kit receptor and its ligand stem cell factor (SCF) in the pathogenesis of the disease was analysed in marrow cell clonogenic assays. We show that the genetic abnormalities in the patient resulted in factor-independent growth and hypersensitivity of primitive progenitors to SCF, with increased production of mast cells. Increased apoptosis and cluster formation, consistent with the myelodysplastic nature of the disorder, accompanied accumulation of abnormal cells with increasing concentrations of SCF.- - - - - - - - - - ranking = 1keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
2/8. Telangiectasia macularis eruptiva perstans and multiple myeloma.The association of mast cell diseases and some hematologic malignancies, usually myeloproliferative disorders, myelodysplastic syndromes, and acute leukemia is well recognized. We report the case of a patient with telangiectasia macularis eruptiva perstans, a rare form of cutaneous mastocytosis, and multiple myeloma, an association that has been described only twice in the literature. Parallel improvement of both conditions was observed under chemotherapy regimens for multiple myeloma. Pathogenesis remains unclear, although the abnormalities in the c-kit pathway may play a role in the proliferation of cells from both lineages.- - - - - - - - - - ranking = 0.78281862296879keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
3/8. Immunohistochemical properties of bone marrow mast cells in systemic mastocytosis: evidence for expression of CD2, CD117/Kit, and bcl-x(L).In an attempt to identify novel diagnostic markers for mast cell (MC)-proliferative disorders, serial bone marrow (bm) sections of 22 patients with mastocytosis (systemic indolent mastocytosis, n = 19; mast cell leukemia [MCL], n = 1; isolated bm mastocytosis, n = 2) were analyzed by immunohistochemistry using antibodies against CD2, CD15, CD29, CD30, CD31, CD34, CD45, CD51, CD56, CD68R, CD117, HLA-DR, bcl-2, bcl-x(L), myeloperoxidase (MPO), and tryptase. Staining results revealed expression of bcl-x(L), CD68R, and tryptase in neoplastic MCs (focal dense infiltrates) in all patients. mastocytosis infiltrates were also immunoreactive for CD45, CD117 (Kit), and HLA-DR. In most cases, the CD2 antibody produced reactivity with bm MCs in mastocytosis, whereas in control cases (reactive bm, immunocytoma, myelodysplastic syndrome), MCs were consistently CD2 negative. Expression of bcl-2 was detectable in a subset of MCs in the patient with MCL, whereas no reactivity was seen in patients with SIM or bm mastocytosis. mastocytosis infiltrates did not react with antibodies against CD15, CD30, CD31, CD34, or MPO. In summary, our data confirm the diagnostic value of staining for tryptase, Kit, and CD68R in mastocytosis. Apart from these, CD2 may be a novel useful marker because MCs in mastocytosis frequently express this antigen, whereas MCs in other pathologic conditions are CD2 negative.- - - - - - - - - - ranking = 0.78281862296879keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
4/8. Persistence of systemic mastocytosis after allogeneic bone marrow transplantation in spite of complete remission of the associated myelodysplastic syndrome.A myelodysplastic syndrome (MDS), type 5 (RAEB-t), and systemic mastocytosis affecting the spleen, the splenic lymph nodes, the bone marrow and the liver were diagnosed in a 38-year-old woman. The clinical course was complicated by splenic vein thromboses and iliac artery embolism. The thrombotic episodes might be secondary to mast cell mediator release. A complete remission of the MDS was obtained by allogeneic bone marrow transplantation, but the mastocytosis persisted. Thus, the possibility that the mast cell originates from a common myeloid precursor cell may be questioned.- - - - - - - - - - ranking = 3.914093114844keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
5/8. Kit ligand/mast cell growth factor-independent differentiation of mast cells in myelodysplasia and chronic myeloid leukemic blast crisis.Autonomous, factor-independent growth and differentiation of malignant cells in preleukemic and leukemic disease states is a well-recognized phenomenon and is often associated with a poor prognosis. mast cells are distinct hematopoietic cells and express a unique profile of antigens. growth and differentiation of normal mast cells is dependent on mast cell growth factor (MGF), the ligand of the c-kit protooncogene product. In this study, we screened for mast cell-lineage involvement in 52 patients suffering from myeloid leukemias, myelodysplastic syndromes (MDS), systemic mastocytosis, or other diseases by probing for mast cell-related molecules (c-kit, tryptase, histamine, and MGF) and by analyzing kit ligand/MGF-independent growth of mast cells in long-term suspension culture. Of the 52 patients tested, 2 patients with refractory anemia with excess of blast cells in transformation and 1 patient suffering from chronic myeloid leukemia blast crisis (CML-BC) were diagnosed as mastocytic disease. These patients were characterized by complex chromosomal abnormalities, splenomegaly, high percentages of circulating metachromatic cells (5% to 25%), high levels of cellular tryptase (> 10 ng/10(5) peripheral blood mononuclear cells/mL) and a tryptase/histamine (ng:ng) ratio greater than 1. The metachromatic cells expressed the mast-cell-related surface antigen c-kit, but not basophil-related antigens (CD11b, CDw17). Furthermore, in these 3 patients, spontaneous, MGF-independent growth of mast cells along with spontaneous synthesis of tryptase was demonstrable in long-term culture. No autocrine production, paracrine production, or overproduction of MGF was found. The spontaneous growth of mast cells could neither be abbrogated by addition of monoclonal antibodies (MoAbs) to c-kit nor by MoAbs against MGF (< 5% inhibition), whereas factor (MGF)-dependent differentiation of mast cells in these patients could be abbrogated by MoAbs to c-kit or MoAbs to MGF (> 70% inhibition, P < .001). In addition, serum MGF levels in these patients were within the normal range and MGF could not be detected in cell-free culture supernatants. All 3 patients showed rapid progression of disease and had a survival time of less than 1 year. In conclusion, we describe a unique form of transformation in MDS and CML-BC characterized by mast cell lineage involvement and factor-independent differentiation of mast cells. This form of leukemic transformation has to be delineated from chronic myeloid leukemia with basophilia or basophil crisis, from primary mast cell leukemia, and from monocytic leukemias and myelodysplastic disorders associated with basophilia.- - - - - - - - - - ranking = 1keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
6/8. Systemic mast cell disease associated with hairy cell leukaemia.Systemic mast cell disease (SMCD) can be regarded as a tumorous proliferation of tissue mast cells involving various organs. The frequency with which SMCD is found in patients with haematological disorders suggests that the association is non-random. The association includes primarily, myeloid disorders such as myelodysplastic syndromes and acute or chronic myeloproliferative disorders. lymphoproliferative disorders may also occur but more rarely, mostly non-Hodgkin's low grade B cell lymphomas. In this report a case is described in which SMCD occurred in a patient with hairy cell leukaemia.- - - - - - - - - - ranking = 0.78281862296879keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
7/8. Detection of mi transcription factor (MITF) mRNA in a case of myelodysplastic syndrome and bone marrow mastocytosis.myelodysplastic syndromes (MDS) may be accompanied by systemic mastocytosis. The mechanisms which play a role in the evolution of mastocytosis, however, are not well understood. We report on a case of refractory and anemia with ringed sideroblasts (RARS), and co-existing bone marrow mastocytosis. Compact mast cell (MC) infiltrates were detected in bone marrow sections by immunohistochemistry using an antibody to tryptase. In addition, the MC were found to express c-kit, the tyrosine kinase receptor for MGF (mast cell growth factor = stem cell factor, SCF). Activating point mutations in the kinase domain of c-kit (often found in mastocytosis) were not detectable. However, the mononuclear cells (MNC) of the bone marrow expressed mRNA specific for MITF, a transcription factor that regulates expression of c-kit and differentiation of MC. Surprisingly, the c-kit ligand SCF was found to augment expression of MITF mRNA in bone marrow MNC. Whether this augmentation represents a general response (preventing loss of growth factor receptor expression during cell maturation) common to all types of hemopoietic progenitors, or is confined to (some forms of) mastocytosis, remains unknown.- - - - - - - - - - ranking = 3.1312744918752keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |
8/8. A case of bone marrow mastocytosis associated with multiple myeloma.mastocytosis is a term used for a spectrum of disorders characterized by abnormal growth and accumulation of mast cells. The cutaneous variants of the disease have to be distinguished from systemic mastocytosis (SM), in which at least one extracutaneous organ is involved. In contrast to cutaneous mastocytosis, SM is often associated with another hematologic neoplasm. In most cases clonal myeloid malignancies such as a myeloproliferative or myelodysplastic syndrome occur. In a few cases of SM, however, clonal lymphoid disorders have been described. We here report on a case of SM associated with multiple myeloma. At first presentation, the 48-year old female patient showed monoclonal IgGlambda gammopathy and bone marrow (BM) mastocytosis, but no BM plasma cell infiltrates. Eight years later, the patient presented with BM mastocytosis and overt multiple myeloma. The co-existence of myeloma and mastocytosis was demonstrable by staining serial BM sections with antibodies against mast cell tryptase, CD68R, and the plasma cell marker VS38c. interphase FISH analysis of BM sections revealed a numeric gain of chromosome 5 and chromosome 7 in the plasma cells but not in the mast cell infiltrates, thereby confirming the presence of two different neoplastic cell populations. To our knowledge, this is the first report describing the co-existence of multiple myeloma and mastocytosis.- - - - - - - - - - ranking = 0.78281862296879keywords = myelodysplastic syndrome, myelodysplastic (Clic here for more details about this article) |