Sequential karyotypic evolutions and bone marrow aplasia preceding acute myelomonocytic transformation from myelodysplastic syndrome

Hypocellular myelodysplastic syndromes: clinical and biological significance

The article is concerned with incidence, clinical features, response to therapy, and prognosis of patients with hypocellular myelodysplastic syndromes. Bone marrow (BM) cellularity <30% (or <20% in patients >70 yr) was found in 24 of 236 (10.2%) trephine biopsies. Median age was 61 yr, with significant male predominance (M/F=3.0) At diagnosis, median hemoglobin was 83 g/L, median platelet and neutrofil counts were 31x109/L and 1.2x109/L, respectively. According to FAB classification, 17 patients had RA, 6 had RAEB, and only 1 had RAEB-t. Beside marrow hypoplasia, the most prominent PH finding was megakaryocyte hypoplasia and dysplasia, found in two-thirds of cases, each. Comparison between hypocellular and normo/hypercellular MDS cases regarding clinicopathological features showed younger age, more severe cytopenia, less blood and BM blast infiltration, MK hypoproliferation, and more pronounced stromal reactions in former cases. Karyotypic abnormalities were present in 12.5% hypocellular cases, in contrast to 44.6% normo/hypercellular cases (p=0.0025). Eleven patients were treated with supportive therapy alone, six with danazol or androgens, six with immunosuppressive therapy, and one with LDARAC. However, complete or partial response was achieved in only four patients treated with danazol or androgens. None of the patients developed leukemia. Eleven patients died, so marrow insufficiency was the main cause of death. Median survival was 33 mo for hypocellular MDS, and 19 mo for normo/hypercellular MDS (p=0.09). The results confirm the existence of hypocellular variant of MDS, which seems to have better prognosis than those patients with normo/hypercellular disease.

Hypocellular myelodysplastic syndromes (MDS): new proposals

To determine whether hypocellular MDS differs from normo/hypercellular MDS, we attempted to identify hypocellular MDS cases either by correcting the bone marrow (BM) cellularity by age (28 patients) or by using a single arbitrary value of BM cellularity (25 patients) and compared these two groups of hypocellular cases to the normo/hypercellular MDS cases (72 patients). 18 patients were common to both hypocellular groups. Patients with hypocellular MDS in both of these selected groups have similar features with regard to age and sex distribution, peripheral blood and bone marrow parameters, FAB subtypes, karyotypes, leukaemic transformation, and survival. However, the median age of patients in < 30% BM cellularity group was higher than those patients in the age-corrected group (69 years v 62 years). The selection of < 30% cellularity excluded 10 cases in the age group < 70 years but included another seven patients in the age group of > 70 years. However, correction of BM cellularity by age revealed that those included patients (selected for < 30% cellularity) who had normocellular BM by their age. Therefore we recommend the age-correcting grouping to ensure comparable series for comparison, for response to treatment, and survival. Finally, BM cellularity does not appear to be an important factor on prognosis in MDS, because patients with hypocellular MDS in both selected groups have similar prognosis to those with normo/hypercellular MDS patients.

Hypoplastic myelodysplastic syndrome: incidence, morphology, cytogenetics, and prognosis

The present study, based upon the retrospective evaluation of 352 patients with primary myelodysplastic syndrome (pMDS), revealed hypoplastic MDS in 42 patients (11.9%). Median age is similar in hypo- and normo-/hypercellular MDS (72.6 versus 70.7 versus 72.4 years). Hypoplastic MDS occurred significantly more often in women compared with normo- and hypercellular MDS. Sequential biopsies were performed in 14 patients, showing a persistence of hypoplasia over a period of up to 43 months. The proportion of patients showing mesenchymal reaction, especially an increase of mast cells, was significantly higher in hypoplastic MDS, whereas dysplastic features of hematopoiesis occurred less frequently and were of lower grade in comparison to normo-/hyperplastic MDS. Among the subgroup with hypoplastic bone marrow, the classification according to FAB criteria revealed 28 patients with RA (66.7%), three with RARS (7.1%), and eight with RAEB (19.0%), as well as one patient each with RAEB-T and CMMol (2.4% each), and one case which had to be reckoned among the category of unclassifiable MDS (2.4%). Median survival was 21.8 months for hypoplastic MDS, 26.9 months for normoplastic MDS, and 14.2 months for hyperplastic MDS. During follow-up, 14 patients (33%) with hypoplastic MDS developed acute nonlymphatic leukemia. Although not a constant finding, karyotype abnormalities involving particularly chromosome 7 seem to be associated with hypoplastic MDS. The results confirm the existence of a hypoplastic variant of MDS which seems to more frequently affect female patients, and which requires bone marrow biopsy for its accurate diagnosis.

Translocation (12;14)(q13;q32) in myelodysplastic syndrome

We report a patient diagnosed with refractory anemia with excess blasts in transformation (RAEB-t) who underwent an evolution to a nonlymphocytic acute leukemia (ANLL-M5a). Initial cytogenetic study showed a diploid karyotype; however, when ANLL-M5a was diagnosed, the bone marrow (BM) cells showed a t(12;14)(q13;q32), which to our knowledge has not been described previously in a myelodysplastic syndrome (MDS).

T-cell receptor γ/δ expressing acute leukemia emerging from sideroblastic anemia: Morphological, immunological, and cytogenetic features

Striking numerical and structural chromosome abnormalities (-Y, +8, i(7q), del (10)(q24), and del (11)(q21)) were detected by cytogenetic analysis in a patient's bone marrow with morphological features of both acute lymphoblastic leukemia and myelodysplastic disorder. Surface marker analysis characterized blast cells to be CD2+ CD7+ CD3+ CD4- CD8- expressing gamma/delta-T-cell receptor antigen and coexpressing CD11b and CD16. Exhibiting an identical phenotype as the leukemic cells, a prominent gamma/delta-TCR+ lymphocyte population was found in the bone marrow as well as in the peripheral blood. Cells of the latter compartment coexpressed CD56 and HLA-DR antigens and exhibited nonspecific cytotoxic activity. In the bone marrow cells NSCA could be induced after stimulation with interleukin 2 in vitro. Morphological, immunological, and cytogenetic findings suggest that gamma/delta-T-ALL emerged from a myelodysplastic disorder after sequential steps of malignant transformation. Leukemic cells with "mixed lineage" character may provide evidence for a common progenitor cell in the bone marrow. Assuming that the leukemic cells represent the malignant counterpart of normal CD3+ gamma/delta-TCR+ cells the results may contribute to our understanding of the origin and differentiation as well as the possible steps of malignant transformation of a gamma/delta-TCR+ lymphocyte population.

Morphologic classification of the myelodysplastic syndromes (MDS): combined utilization of bone marrow aspirates and trephine biopsies

In a retrospective and prospective follow-up study from 1975 to 1991, bone marrow biopsies, aspirates and clinical features of 495 patients with MDS were investigated. Sections of undecalcified plastic embedded biopsies and smears of bone marrow aspirates were stained according to Giemsa. Bone marrows with MDS were characterized by three main categories of morphologic alterations: (1) cellular abnormalities, (2) architectural disorganization in the bone marrow and (3) stromal changes; the combined use of aspirates and trephine biopsies enabled a more reliable and accurate diagnosis of MDS than either one alone. The bone marrow findings fell into one of 7 subtypes, with the frequencies and median survivals in brackets: (1) MDS sideroblastic (19%, 62 months), (2) MDS megaloblastoid (13%, 56 months), (3) MDS proliferative (22%, 31 months), (4) MDS blastic (15%, 9 months), (5) MDS hypoplastic (15%, 26 months), (6) MDS fibrotic (6%, 29 months), and (7) MDS inflammatory (10%, 42 months). In follow-up studies patients with secondary MDS were excluded and the prognosis and subsequent evolution for each of the morphologic subtypes were evaluated. The conclusion is drawn that aspirates and trephine biopsies are complementary procedures and both are required for diagnosis, classification and decisions on current treatment modalities of patients with MDS.

Appearance time of leukemic cells with t(8;21) in bone marrow

A 30-year-old man was referred because of slight leukocytosis. The hematological findings, including those of the bone marrow, showed no evidence of leukemia. The level of neutrophil alkaline phosphatase (NAP) in the peripheral blood was normal, as were the chromosomes from bone marrow cells. Fifteen months later, the disease was diagnosed as M2 (according to the French-American-British classification) showing a t(8;21)(q22;q22) and a low NAP level as two markers of M2 cells. This is probably the first case of acute leukemia in which the cytogenetic analysis was performed before and after the appearance of a specific chromosome abnormality.

Myelodysplastic syndromes

A cure for MDS has yet to be found. The aim of therapy is to attempt to restore normal hematopoiesis and prevent evolution to acute leukemia. The major trend is supportive care. Blood counts and bone marrow aspirations are taken to evaluate the disease, and transfusions of blood products and antibiotics are given when necessary. A new encouraging modality of therapy is the use of hematopoietic growth factors to reverse cytopenias. As there is no curative treatment for MDS, the patient is likely to be offered investigational drugs either singly or in combination. Future trends in the treatment of MDS will be combinations of agents including biological agents with retinoic acid or vitamin D, low-dose Ara-C, the interferons, and colony-stimulating factors.

Biclonal chromosome evolution of chronic myelomonocytic leukemia in a child

A monosomy 7 was first detected in a 6-month-old boy with a chronic myelomonocytic leukemia. After etoposide treatment, relapse occurred after 29 months, with transformation of the disease into an acute myeloblastic leukemia. After bone marrow transplantations, two abnormal clones were found in marrow cells: 45,XY,-7,del(12)(p11p12)(66%), and 45,XY,-7,t(3;12)(q26;p12)(33%). Several karyotypic studies performed until the terminal phase exhibited the persistence of these two clones in the same proportion, although both independently acquired additional and often similar anomalies. The clone with t(3;12) acquired der(7),der(11),der(17),der(8),der(10),-5,-20, and the clone with del(12p), del(5q),der(4),der(8),der(10),der(17),-5,-20. The anomalies in 12p12 appear to represent an important although secondary event of the neoplastic process. The other anomalies may correspond to either those of a secondary acute nonlymphocytic leukemia, since they occurred after treatment by etoposide and alkylating agents, or to the natural evolution of myelomonocytic leukemia.

Pathogenetic implications of internuclear bridging in myelodysplastic syndrome. An Eastern Cooperative Oncology Group/Southwest Oncology Group Cooperative Study

Numerous morphologic features have been described in bone marrow and peripheral blood in myelodysplastic syndrome (MDS). We draw attention to a high incidence of a subtle morphologic feature, internuclear bridging (INB), not previously recognized as a morphologic feature in MDS. The occurrence of INB in MDS suggests an underlying abnormality of mitotic division that could explain the impaired production of hematopoietic cells, the addition and deletion cytogenetic changes, and the stepwise disease progression and cytogenetic progression characteristic of MDS. Lack of awareness that INB occurs in MDS may cause confusion of MDS and congenital dyserythropoietic anemia type I, a congenital process also characterized by INB.

Biology of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a diverse spectrum of disorders ranging from refractory anemia to a preleukemic state. Peripheral cytopenias, cellular marrow, dysplasias and dysfunctions of myeloid and lymphoid cells constitute hematological hallmarks, and are caused by ineffective hemopoiesis. Investigations of cell cultures and cellular functions indicate that the disease originates in a stem cell pluripotent to all myeloid cells and possibly lymphoid cells as well. The disease commonly runs a chronic indolent course, often terminating in acute leukemia or nonleukemic death, notably infections and/or hemorrhage due to cytopenias and cellular dysfunctions. Clonal expansion or clonal evolution appears to be related to the disease progression with a greater degree of malignancy. However, the initial sequence of events causing damage to stem cells is still undefined.

Chromosomal subclonal evolution in paroxysmal nocturnal hemoglobinuria evolving into acute megakaryoblastic leukemia

Four cytogenetic studies were performed in the course of a paroxysmal nocturnal hemoglobinuria evolving into acute megakaryoblastic leukemia. The clonal evolution was characterized by a unique structural change (9p) at the time of diagnosis, heralding an accelerated and complex karyotypic alteration including 5q-, 12p-, +21, -5, -7. At the terminal phase, the initial population was replaced within 1 week by a new overgrowing clone with -5, +8, +17. This suggests that the paroxysmal nocturnal hemoglobinuria-associated preleukemia and leukemic states share with acute nonlymphocytic leukemia the same nonrandom chromosomal changes.

Myelodysplastic syndromes: their history, evolution and relation to acute myeloid leukaemia

The myelodysplastic syndromes (MDS) constitute a heterogeneous group of clonal disorders arising from a multipotent haemopoietic progenitor which share a leukaemic propensity, 30% of cases culminating in acute myeloid leukaemia (AML). Their pathogenesis probably entails multiple steps, phenotypic progression being determined by either expansion or evolution of the abnormal clone. The clonal origin of certain cases of de novo AML is analogous to that of MDS and evidence that they share a common pathogenesis and distinct biological characteristics is beginning to emerge.

Abnormalities of the short arm of chromosome 12 in acute nonlymphocytic leukemia and dysmyelopoietic syndrome

Abnormalities of the short arm of chromosome #12 (12p) were found in 18 patients, 7 with previously untreated acute nonlymphocytic leukemia (ANLL) and 11 with dysmyelopoietic syndromes (MDS) or ANLL following treatment for another malignant disease. The chromosome #12 abnormality was a partial deletion in 15 patients and a translocation in 3. The 12p- was the sole chromosomal abnormality in seven patients (four with de novo ANLL) and was associated with other chromosome abnormalities in eight patients. Thus, partial monosomy for 12p was often associated with other chromosomal changes and was a secondary abnormality in some cases. The consequences of this hemizygosity for genes located at 12p are discussed with references to the possible expression of a potentially mutated recessive gene. The study of c-K-ras 2, normally located at 12p, must be done in such cases, as the association of secondary blood disorders and multiple chromosome abnormalities suggests a possible mutation of this c-oncogene on chromosome #12.

Chromosomal changes in secondary leukemias of childhood and young adulthood

The increasing success of antineoplastic therapy has resulted in a growing number of long-term survivors. These people are at risk for complications of the therapy itself. Among these induced acute nonlymphoid leukemia (ANLL) has been both common and often lethal. We reviewed 72 recently reported patients under 30 years of age at the time of initial diagnosis who developed a secondary, karyotypically defined leukemia. Fifty-eight patients contracted ANLL a mean of 4 1/2 years from the initial diagnosis. In 25 patients, this was preceded by a preleukemic phase characterized by a hypercellular bone marrow with abnormal precursors, often accompanied by peripheral pancytopenia, that lasted a mean of 6 months. Three additional patients died in this preleukemic phase. In all 61, the most common chromosomal abnormalities were numerical errors. Twenty-four patients had a hypodiploid karyotype, most often in those in whom the primary diagnosis was lymphoma (22 of 43). The most common chromosomes missing in whole or in part were number 7 (18 patients), number 5 (8 patients), number 17 (5 patients), and number 21 (4 patients). The anomalies were frequently multiple and complex. Monosomy 7 figured particularly strongly and may be similar to a karyotypically identical myeloproliferative disorder characterized by micromegakaryocytes, giant platelets, and abnormal granulocyte function arising de novo in children. These findings are similar to those in older patients with ANLL induced by environmental carcinogens or antineoplastic therapy. They are different from the karyotypic changes seen in de novo ANLL in children and young adults, suggesting a different etiology. Also, they reinforce the need to find less leukemogenic treatment programs.

Myelodysplastic syndromes: pathogenesis, functional abnormalities, and clinical implications

The myelodysplastic syndromes represent a preleukaemic state in which a clonal abnormality of haemopoietic stem cell is characterised by a variety of phenotypic manifestations with varying degrees of ineffective haemopoiesis. This state probably develops as a sequence of events in which the earliest stages may be difficult to detect by conventional pathological techniques. The process is characterised by genetic changes leading to abnormal control of cell proliferation and differentiation. Expansion of an abnormal clone may be related to independence from normal growth factors, insensitivity to normal inhibitory factors, suppression of normal clonal growth, or changes in the immunological or nutritional condition of the host. The haematological picture is of peripheral blood cytopenias: a cellular bone marrow, and functional abnormalities of erythroid, myeloid, and megakaryocytic cells. In most cases marrow cells have an abnormal DNA content, often with disturbances of the cell cycle: an abnormal karyotype is common in premalignant clones. Growth abnormalities of erythroid or granulocyte-macrophage progenitors are common in marrow cultures, and lineage specific surface membrane markers indicate aberrations of differentiation. Progression of the disorder may occur through clonal expansion or through clonal evolution with a greater degree of malignancy. Current attempts to influence abnormal growth and differentiation have had only limited success. Clinical recognition of the syndrome depends on an acute awareness of the signs combined with the identification of clonal and functional abnormalities.