Refractory thrombocytopenia with chromosome 11q23 abnormality

Clinico-hematologic features of myelodysplastic syndrome presenting as isolated thrombocytopenia: an entity with a relatively favorable prognosis

The existence of isolated cytopenia in myelodysplastic syndrome (MDS) has been described, however, the exact clinico-hematologic features of such MDS patients are still obscure. The aim of this study was to provide additive clinico-hematologic information on MDS patients with isolated thrombocytopenia in comparison with idiopathic thrombocytopenic purpura (ITP). We searched for MDS with isolated thrombocytopenia in 146 sequential patients with MDS and evaluated their clinical features at the time of MDS diagnosis. We found 13/146 (8.9%) patients with MDS showing isolated thrombocytopenia. These patients were male predominant (10:3) and were all diagnosed as refractory anemia after reassessment of marrow findings, however, two of them had an initial diagnosis of ITP. Leukemic transformation was rarely noted (1/13 patients), but 1 patient developed myelofibrosis. Cytogenetic study demonstrated that 3 patients had del(20q), 2 had t(1;7)(q10;p10), and 5 showed normal karyotypes. The most prominent morphologic feature in the megakaryocytes was the presence of micromegakaryocytes (5/13) and 8/13 had hypogranulated neutrophils, whereas pseudo-Pelger nuclear anomaly was rarely detectable. Of note is that 7/13 patients had an increased number of megakaryocytes in the marrow. Most patients survived for more than 2 years. Approximately 9% of MDS patients showed isolated thrombocytopenia and most of them had a favorable prognosis. Some MDS patients with isolated thrombocytopenia have been mistakenly diagnosed as having ITP, since approximately 50% of our MDS patients with isolated thrombocytopenia had an increased number of megakaryocytes with low grade dysplasia. Therefore, careful attention to differential diagnosis is recommended for these patients.

Clinical analysis and TPO levels in three patients with refractory thrombocytopenia

Refractory thrombocytopenia (RTC) is a counter-concept to refractory anemia, which is characterized by isolated thrombocytopenia associated with clonal chromosomal abnormality. The diagnosis of RTC is difficult to establish based on morphologic features alone. And steroid therapy for RTC is often ineffective. We examined 3 patients with RTC to identify its characteristics and measured serum thrombopoietin levels. The mean platelet count was 5.1 x 10(4)/microl and the mean age was 64 years. None of our patients had clinical nor laboratory evidence of liver dysfunction, renal disease or disseminated intravascular coagulation. All patients were negative for antiplatelet antibody, PA-IgG and anticardiolipin-beta2GPI antibody. Leukocyte alkaline phosphatase level was low in two patients. Clonal chromosomal abnormalities of different types were detected in all patients. Bone marrow smears showed micromegakaryocytes. But there were no apparent morphological abnormalities of erythroid and granuloid series. Thrombopoietin levels, as determined by enzyme-linked immunosorbent assay, varied from <0.2 to 1.40 fmol/ml. We could not find the screening tool of RTC. In conclusion, there is a need to identify RTC from isolated thrombocytopenia because the patients with RTC don't have good prognosis as patients with isolated thrombocytopenia. Cytogenetic analysis is necessary to establish the diagnosis of RTC. We recommend that a patient above 50 years of age presenting with isolated thrombocytopenia and a low leukocyte alkaline phosphatase score should be suspected of having RTC.

Molecular features of primary MDS with cytogenetic changes

Cytogenetic changes in primary myelodysplastic syndromes (MDS) have been extremely useful to identify clonality and to define specific clinico-pathological entities. More recently, with the development of DNA technology, a bulk of new information has been added to classical cytogenetics. Genes corresponding to chromosomal breakpoints implicated in reciprocal translocations have been cloned. Search for the minimal lost region has been the aim of the so-called deletion mapping approach to pick up the hypothetical suppressor gene(s) critical for typical deletions of MDS. Correlation has been found between gene mutations, deletions, expression, and clinical-hematological or cytogenetic features of MDS. Integration of fluorescence in situ hybridization at DNA level and of immunophenotyping at cellular level is an elegant tool to investigate clonal affiliation in MDS with distinct genetic changes.