Transformation of chronic myelomonocytic leukemia to acute lymphoblastic leukemia: case report and review of the literature of lymphoblastic transformation of myelodysplastic syndrome

Progression in Myeloid Neoplasms: Beyond the Myeloblast

Disease progression in myelodysplastic syndromes (MDS), myelodysplastic-myeloproliferative neoplasms (MDS/MPN), and myeloproliferative neoplasms (MPN), altogether referred to as myeloid neoplasms (MN), is a major source of mortality. Apart from transformation to acute myeloid leukemia, the clinical progression of MN is mostly due to the overgrowth of pre-existing hematopoiesis by the MN without an additional transforming event. Still, MN may evolve along other recurrent yet less well-known scenarios: (1) acquisition of MPN features in MDS or (2) MDS features in MPN, (3) progressive myelofibrosis (MF), (4) acquisition of chronic myelomonocytic leukemia (CMML)-like characteristics in MPN or MDS, (5) development of myeloid sarcoma (MS), (6) lymphoblastic (LB) transformation, (7) histiocytic/dendritic outgrowths. These MN-transformation types exhibit a propensity for extramedullary sites (e.g., skin, lymph nodes, liver), highlighting the importance of lesional biopsies in diagnosis. Gain of distinct mutations/mutational patterns seems to be causative or at least accompanying several of the above-mentioned scenarios. MDS developing MPN features often acquire MPN driver mutations (usually JAK2), and MF. Conversely, MPN gaining MDS features develop, e.g., ASXL1, IDH1/2, SF3B1, and/or SRSF2 mutations. Mutations of RAS-genes are often detected in CMML-like MPN progression. MS ex MN is characterized by complex karyotypes, FLT3 and/or NPM1 mutations, and often monoblastic phenotype. MN with LB transformation is associated with secondary genetic events linked to lineage reprogramming leading to the deregulation of ETV6, IKZF1, PAX5, PU.1, and RUNX1. Finally, the acquisition of MAPK-pathway gene mutations may shape MN toward histiocytic differentiation. Awareness of all these less well-known MN-progression types is important to guide optimal individual patient management.

Occurrence of a Clonal T-Cell Population in a Case of Chronic Myelomonocytic Leukemia

Chronic myelo-monocytic leukemia (CMML) is an aggressive myeloid neoplasm with some features of a myelodysplastic syndrome (MDS) and others of a myeloproliferative neoplasm (MPN). Rarely, patients with CMML have a co-existing lympho-proliferative disorder (LPD). In most cases, the lymphoid neoplasm is diagnosed first, and the CMML is considered to be a secondary therapy-induced form of leukemia. We report herein a unique case of de-novo CMML, with an underlying clonal T-cell population and describe its clinical presentation and laboratory findings. A 70-year old male presented with a 3-month history of cough, dsypnea, abdominal distension, and low-grade fever. Physical and radiological examination revealed hepatosplenomegaly but no lymphadenopathy. Peripheral blood had absolute monocytosis with marrow showing CMML with 10% blasts along with dysplasia in myeloid and erythroid lineages. Flow cytometry indicated possibility of chronic myelo-monocytic leukemia with 13% monocytic cells along with an additional clonal population of gamma/delta T cells (15%) with aberrant immunophenotype. Polymerase chain reaction (PCR) analysis was positive for clonal T-cell rearrangement. A diagnosis of CMML with an underlying clonal T-CLPD was made. The synchronous occurrence of CMML and T-cell neoplasm may be attributed to a genetic mutation common to both. Currently, there are no treatment guidelines for group of patients; hence individualized therapeutic strategies should be implemented to enable symptomatic improvement and provide optimum care.

Progression, transformation, and unusual manifestations of myelodysplastic syndromes and myelodysplastic-myeloproliferative neoplasms: lessons learned from the XIV European Bone Marrow Working Group Course 2019

Disease progression in myelodysplastic syndromes (MDS) and myelodysplastic-myeloproliferative neoplasms (MDS/MPN) is a major source of mortality. The European Bone Marrow Working Group organized a dedicated workshop to address MDS and MDS/MPN progression, and myeloid neoplasms with histiocytic and lymphoblastic outgrowths in 2019 in Frankfurt, Germany. In this report, we summarize clinical, histopathological, and molecular features of 28 cases. Most cases illustrate that prognostic mutational profiles change during follow-up due to accumulation of high-risk mutations in the trunk clone, and that results from repeated molecular testing can often explain the clinical progression, suggesting that regular genetic testing may predict transformation by early detection of aggressive clones. Importantly, identical mutations can be linked to different clinical behaviors or risks of fibrotic progression and/or transformation in a context-dependent manner, i.e., MDS or MDS/MPN. Moreover, the order of mutational acquisition and the involved cell lineages matter. Several cases exemplify that histiocytic outgrowths in myeloid neoplasms are usually accompanied by a more aggressive clinical course and may be considered harbinger of disease progression. Exceptionally, lymphoblastic transformations can be seen. As best estimable, the histiocytic and lymphoblastic compounds in all occasions were clonally related to the myeloid compound and-where studied-displayed genomic alterations of, e.g., transcription factor genes or genes involved in MAPK signaling that might be mechanistically linked to the respective type of non-myeloid outgrowth.

Characterization of myelodysplastic syndromes progressing to acute lymphoblastic leukemia

Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases, with a variable probability of transformation into acute leukemia, which is, in the vast majority of cases, of myeloid lineage. Nevertheless, rare cases of acute lymphoblastic leukemia in patients with previously diagnosed MDS have been reported. We describe a series of 3 cases of MDS/CMML marked with evolution to acute lymphoblastic leukemia (ALL) and provide a comprehensive review of the 49 cases documented in the literature so far. These sporadic events have only been published as single-case reports or small series to date. Such atypical cases emphasize the possibility of major phenotypic switches arising at the leukemic stem cell (LSC) and/or early progenitor levels, as a consequence of epigenetic and genomic events driving these changes in the bone marrow niche.

Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions

Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm characterized by dysplasia, abnormal production and accumulation of monocytic cells and an elevated risk of transforming into acute leukemia. Over the past two decades, our knowledge about the pathogenesis and molecular mechanisms in CMML has increased substantially. In parallel, better diagnostic criteria and therapeutic strategies have been developed. However, many questions remain regarding prognostication and optimal therapy. In addition, there is a need to define potential pre-phases of CMML and special CMML variants, and to separate these entities from each other and from conditions mimicking CMML. To address these unmet needs, an international consensus group met in a Working Conference in August 2018 and discussed open questions and issues around CMML, its variants, and pre-CMML conditions. The outcomes of this meeting are summarized herein and include diag nostic criteria and a proposed classification of pre-CMML conditions as well as refined minimal diagnostic criteria for classical CMML and special CMML variants, including oligomonocytic CMML and CMML associated with systemic mastocytosis. Moreover, we propose diagnostic standards and tools to distinguish between 'normal', pre-CMML and CMML entities. These criteria and standards should facilitate diagnostic and prognostic evaluations in daily practice and clinical studies in applied hematology.

Serum amyloid A1 and plasminogen as predictory proteins to monitor the progression of preleukemic diseases towards acute lymphoblastic leukaemia

SAA1 and plasminogen as additional predictory molecules to monitor the progression of preleukemic diseases towards ALL.

RARS with fibrosis and del(20q) transformed into ALL

Transformation of myelodysplastic syndrome (MDS) into acute myelogenous leukemia occurs in approximately 30 % of cases, while progression into acute lymphoblastic leukemia (ALL) is rare. We report on a 67-year-old man with the diagnosis of MDS, subtype refractory anemia with ring sideroblasts (RARS), karyotype 20q- , JAK-2 negative and grade III fibrosis on the bone marrow biopsy, who evolved into ALL 33 months after the diagnosis of MDS. RARS is one of the subtypes of MDS with most indolent course. Deletion of the long arm of chromosome 20 (20q-) is considered as good prognosis by the International Prognostic Scoring System, an important scoring system for predicting survival and evolution of MDS. Primary MDS with bone marrow fibrosis may represent a distinct clinicopathological and is supposed to have an unfavorable prognosis. The combined analysis of these features makes this rare report still more challenging and illustrates that biology of MDS is yet to be discovered.

Myelodysplastic syndrome with myelofibrosis transformed to a precursor B-cell acute lymphoblastic leukemia: a case report with review of the literature

Myelodysplastic syndromes (MDS) comprise a group of heterogeneous clonal hematopoietic cell disorders characterized by cytopenias, bone marrow hypercellularity, and increased risk of transformation to acute leukemias. MDS usually transformed to acute myeloid leukemia, and transformation to acute lymphoblastic leukemia (ALL) is rare. Herein, we report a unique patient who presented with MDS with myelofibrosis. Two months after the initial diagnosis, she progressed to a precursor B-cell acute lymphoblastic leukemia. She was treated with induction therapy followed by allogenic stem cell transplantation. She was alive and doing well upon last followup. We have also reviewed the literature and discussed the clinicopathologic features of 36 MDS patients who progressed to ALL reported in the literature.

Transformation of childhood MDS-refractory anemia to acute lymphoblastic leukemia

Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic stem cell. Patients have a deteriorating course with about 30% evolving into acute leukemias usually of the myeloid phenotype. Evolution into acute lymphoblastic leukemia is a rare and intriguing phenomenon seen in far less than 1% of adult cases, and extremely rare in pediatric population. We report a case of childhood MDS-refractory anemia transforming into acute lymphoblastic leukemia after an interval of 21 months since presentation and being on cyclosporine therapy for 9.5 months. The case raises further questions about the biology of MDS and the potential role of cyclosporine in leukemic transformation.

Maturation-associated immunophenotypic abnormalities in bone marrow B-lymphocytes in myelodysplastic syndromes

Recent studies concerning the pathophysiology of myelodysplastic syndromes (MDS) have shown evidences for the existence of complex interactions between hematopoietic stem cells and the bone marrow (BM) microenvironment. We analyzed the B-lymphocyte maturation in BM of patients with MDS. For this purpose, 41 newly-diagnosed patients were analyzed. Enumeration and characterization of CD34+ and CD34- B-cell precursors and mature B-lymphocytes was performed using multiparameter flow cytometry. BM from eight transplant donors and six orthopedic surgery patients were used as controls. CD34+/CD45(lo) B-cells were found in 17/22 patients with RA/RARS and in 5/13 with RAEB. In patients with RAEB-t and CMML no CD34+ B-cell precursors could be detected. A positive correlation was found between CD34+ and CD34- B-cell precursors (r=0.52). CD34+ B-cell precursors presented an inverse correlation with BM percentage of blasts and peripheral leukocytes and a positive one with hemoglobin. Asynchronous antigen expression (CD19+/CD79a- cells) was found in 7/11 cases of RA/RARS and 6/18 cases of RAEB in which this phenotype was examined. Abnormal patterns of expression for at least one antigen was found in 91% of RA/RARS cases and in 74% of RAEB. Underexpression of TdT and CD79a were the most frequent abnormalities. Our results present evidences of an abnormal B-cell maturation in MDS. This may be an evidence that B-lymphocytes are derived of the abnormal clone. But it may also be the consequence of influences of abnormalities of BM microenvironment leading to an impaired commitment and maturation of the B-cell line in MDS. Studies performed with purified well-characterized B-cells may further elucidate these abnormalities.

Advances in the pathological diagnosis and biology of acute lymphoblastic leukemia

An accurate diagnosis of acute lymphocytic leukemia requires careful examination of the morphology, immunophenotype, genetic features, clinical characteristics, and molecular findings. This multiparametric approach should be used to achieve optimal evaluation of every suspected case of acute lymphocytic leukemia.

Progression of myelodysplasia to acute lymphoblastic leukaemia: implications for disease biology

Myelodysplastic syndrome (MDS) comprises a group of clonal haematopoietic disorders characterized by peripheral blood cytopenias, bone marrow hypercellularity, and abnormal blood cell differentiation. Approximately 30% of cases of MDS eventually progress to acute myelogenous leukemia (AML), while progression of MDS into acute lymphoblastic leukemia (ALL) is rare. In this report, we describe a case of MDS that progressed to ALL, and review the 21 previously reported cases of MDS to ALL transformation. We review the cancer stem cell model and its application to these disorders, and discuss the implications of the rarity of transformation of MDS to ALL for the biology of MDS and the pathogenesis of ALL.

Transformation of Myelodysplastic Syndrome to Acute Lymphoblastic Leukemia: A Case Report and Review of the Literature

Myelodysplastic syndrome (MDS) often transforms into acute leukemia, usually of a myeloid phenotype. However, the transformation of MDS into acute lymphoblastic leukemia (ALL) is extremely rare. We present a case of refractory anemia with excess of blasts (RAEB) that transformed into ALL. MDS (RAEB) was diagnosed in a 68-year-old Japanese woman in August 2001. Two months later, MDS progressed to erythroleukemia (French-American-British [FAB]classification, acute myeloid leukemia [AML]-M6), and in December, 2001, she was treated with combined chemotherapy containing aclarubicin, cytarabine, and granulocyte colony-stimulating factor, which improved her clinical symptoms. However, 1 month after the chemotherapy, she developed ALL. The blasts at that time had a markedly basophilic cytoplasm with multiple cytoplasmic vacuoles, and their morphology mimicked that of ALL-L3. The blasts also expressed CD13, a myeloid marker, in addition to lymphoid markers. Southern-blot analysis revealed rearrangement of the immunoglobulin heavy chain, but no additional chromosomal abnormality characteristic of ALL-L3 was detected. The patient was treated with chemotherapy, but she developed tumor lysis syndrome and died of multiple organ failure. Although the precise mechanism of lymphoid transformation is not yet fully understood, this case clinically supports the nature of MDS as a pluripotent hematopoietic stem cell disorder.

Malignant hematological disorders in children with Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome (WHS) is a rare chromosomal disorder attributable to a deletion at the short arm of chromosome 4. This syndrome is associated with characteristic facial appearance, multiple congenital abnormalities, mental retardation, feeding difficulties and failure to thrive. We report two girls with WHS who developed myelodysplastic syndrome (MDS). According to the "Category, Cytology, Cytogenetic (CCC)"classification of childhood MDS, patient 1 had refractory cytopenia with ring sideroblasts at the age of 6 years, while patient 2 had refractory cytopenia with dysplasia at the age of 5-1/2 years. Patient 1 progressed to refractory cytopenia with excess blasts within a year, while patient 2 progressed to acute lymphoblastic leukemia within 1 month of presentation. It is possible that allelic loss of a tumor suppressor gene such as WHSC1 and/or FGFR3 from the deleted segment 4p16.3 plays a critical role in the process of malignant transformation. To our knowledge, this is the first report of severe hematological complications like MDS and leukemia in children with WHS and may be an important genetic model for understanding malignant hematological transformation. This report also underscores the importance of evaluating children with WHS for hematopoietic dysfunction.

Burkitt's acute lymphoblastic leukaemia transformation after myelodysplastic syndrome

We describe a patient with myelodysplastic syndrome (MDS) that transformed to Burkitt's acute lymphoblastic leukaemia (ALL). The leukaemic blasts were negative for peroxidase staining, and expressed CD10, CD19, CD22, CD38, human leucocyte antigen (HLA)-DR and surface immunoglobulin (sIg) M, but neither sIgD nor sIgG were expressed. Chromosomal study during the ALL phase showed t(8;22)(q24;q11) in addition to the karyotypes determined during the MDS phase. Furthermore, overexpression of c-myc mRNA was confirmed in ALL blasts. These findings indicate that MDS transformed to Burkitt's ALL through multiple cytogenetic evolutions, the final event of which seems to be overexpression of the c-myc gene.

Clonality in the myelodysplastic syndromes

The myelodysplastic syndromes (MDSs) comprise a heterogeneous group of stem cell disorders involving cytopenia and dysplastic changes in 3 hematopoietic lineages. Although it is accepted that MDS is a clonal disorder, the exact nature of the involvement of multipotent stem cells and progenitor cells has not been resolved. Most clonality studies of MDS support the proposal that the primary neoplastic event occurs, in most patients, at the level of a committed myeloid progenitor cell, capable of differentiation into multiple myeloid lineages. The extent of the involvement of T and B lymphocytes in MDS remains controversial. Much of the variation reported may result from disease heterogeneity and technical issues such as skewed methylation patterns occurring in studies analyzing X-chromosome inactivation patterns (XCIP) and possible impurities in lymphocyte preparation. A great deal of the evidence in support of T-lymphocyte involvement in MDS has been generated by XCIP studies, and some of these data need to be treated with caution, especially data from studies in which appropriate controls were omitted. In contrast, B-lymphocyte involvement in some patients with MDS is based on studies using more robust technology including combined immunophenotyping and fluorescence in situ hybridization. Clonality studies involving myeloid and lymphoid cells in MDS have yielded discrepant results with regard to the potential involvement of multipotent (lympho-myeloid) hematopoietic stem cells (HSCs). However, failure to detect a clonal marker in all cells of all lineages does not preclude multipotent-HSC involvement. Some recent studies have produced compelling evidence to show that, in some patients with MDS, the multipotent HSC is the target of the primary neoplastic event. It now seems probable that MDS arises in multipotent HSCs more commonly than previously recognized. Such data not only provide important new insights into the biology of MDS but also may have therapeutic implications. The determination of whether multipotent HSCs are involved in the MDS clone may be important for the use of autologous stem cell transplantation in these patients.

DNA content of granulocytes, monocytes, and lymphocytes in the bone marrow smears of patients with myelodysplastic syndromes

Recently, we have reported a high incidence of DNA hypodiploidy defined as DNA index (DI) in blasts/promyelocytes from 39 patients with myelodysplastic syndromes (MDS) found to be without a relationship to cytogenetics. In the present study the DNA content (DI) in granulocytes, monocytes, and lymphocytes measured in the same bone marrow smears from the above patients are reported. DNA hypodiploidy was found in mature cells, not only in myeloid cells (granulocytes and monocytes) but also in lymphocytes. A lower mean DI in each cell type of patients compared to controls was found. Pairwise comparison of the mean DI (+/-SE) in 32 patients with normal (n = 22) and abnormal (n = 10) cytogenetics and controls (n = 8) showed a significantly (P < 0.01) lower value for each group of patients, respectively, in all cell types. No difference was found between the two groups of patients. Presence of weak-Feulgen stained nuclei (DI < 0.40) in granulocytes and monocytes was more pronounced in patients expressing DNA hypodiploid immature cell populations, but only occasionally in lymphocytes, suggesting a link to an apoptotic event and intramedullary cell death. DNA hypodiploidy is shown to be a common feature even in mature cell populations in MDS bone marrows. Clonality, by means of DNA content, appears reasonable as regards the granulocytes and monocytes. DNA hypodiploid lymphocytes, on the other hand, might be small blasts (stem cells) or dying cell populations of unknown origin.

Pathologic diagnosis of acute lymphocytic leukemia

With present knowledge, the optimal management of individual patients with acute leukemia requires that every case be studied by morphology, cytochemistry, cytogenetic, immunologic and molecular techniques. An algorithm for diagnostic evaluation and classification of ALL is provided in Fig. 11. Other techniques, such as DNA or cDNA [figure: see text] microarray, are at present important research tools but have not yet had a major effect on patient care. More detailed studies of individual patients need to be conducted at specialized cancer centers, where preservation of cells, DNA, RNA, or protein is possible. Such investigations will yield important information on the clinical importance of the expression of various markers, the prevalence and relevance of bilineage and biphenotypic leukemias, and above all will reveal the mechanisms of leukemogenesis and of disease evolution. Such insights will further aid clinicians in treating ALL and in preventing refractory disease.

Combined immunophenotyping and FISH identifies the involvement of B-cells in 5q- syndrome

The 5q- syndrome is a distinct subtype of myelodysplastic syndrome (MDS) characterized by refractory anemia, deletion of the long arm of chromosome 5, del(5q), as the sole cytogenetic abnormality, and a low frequency of transformation to acute leukemia. Using combined immunophenotyping and fluorescence in situ hybridization (FISH), studies were carried out on bone marrow smears of three 5q- syndrome cases to identify the cell lineages carrying the 5q deletion. In all three cases, the granulocytic, monocytic, and erythroid lineages possessed the del(5q) clonal marker, whereas the T-lymphocytes did not. Interestingly, in one case, cells of B-lymphoid lineage also showed the presence of the del(5q). This is the first report to date showing involvement of an acquired 5q deletion associated with MDS in B-cells. This result suggests that in some cases, MDS arises in a multipotent cell with a capacity to differentiate into both myeloid and lymphoid cells.

Childhood myelodysplastic syndromes in a Brazilian population

Fourteen pediatric cases of myelodysplastic syndrome according to French-American-British Co-operative Group (FAB) criteria were identified in a retrospective review of all cases of hematologic malignancies referred to the Pediatric Oncology division of the Cancer Hospital A. C. Camargo over a 12-year period: 1 case of refractory anemia, 8 cases of refractory anemia with excess of blasts, and 1 case of refractory anemia with excess of blasts in transformation. Three children had features consistent with chronic myelomonocytic leukemia, and one child was diagnosed with secondary myelodysplastic syndrome. The median age was 3.5 years (1 month-11 years). In 11/14 cases the disease evolved to acute leukemia. In 3 patients blasts had morphological and cytochemical features of lymphoblasts. Two of these patients had a good response to acute lymphoblastic leukemia chemotherapy protocol. The time of progression to leukemia in these cases was shorter than in those who evolved to acute myeloid leukemia. The authors believe this to be the first series of pediatric myelodysplastic syndrome documented in Brazil. Cases were characterized by aggressive FAB type, conspicuous cell atypias in all 3 hemopioetic cell lines, and a high rate of evolution to acute leukemia.

Multiple lymphoid nodules in bone marrow have the same clonality as underlying myelodysplastic syndrome recognized with fluorescent in situ hybridization technique

Benign nodular lymphoid lesions are not rare in the bone marrow of patients with myelodysplastic syndrome (MDS). Herein, we report a case of MDS with clonal lymphoid aggregates in the bone marrow but without evidence of systemic lymphoma. The case of a 71-year-old man was evaluated for cytopenia. His bone marrow was initially hypocellular, with 10% blasts and a few small lymphoid aggregates. The diagnosis of refractory anemia with excess blasts was made. The disease progressed gradually, and he received erythropoietin and granulocyte colony-stimulating factor for a short time. Forty-two months later, acute leukemia (M1) developed, with 60% to 70% blasts in the bone marrow. The bone marrow also showed large aggregates of lymphocytes. Immunohistochemical study of these cells in the nodular lesions showed 50% CD3+ and 50% CD20+. Cytogenetic and molecular genetic studies revealed monosomy 7 and T- and B-cell clonal gene rearrangement. Fluorescent in situ hybridization study with centromere-specific probes of a bone marrow specimen showed monosomy 7 in both nodular lymphoid lesions and surrounding bone marrow cells, indicating that both processes originated from the same abnormal pluripotential progenitor.

Lymphoblastic transformation of myelodysplastic syndrome

Mielodysplastic syndromes (MDS) are clonal disorders of the hemopoietic stem cell. About one third of the cases terminate in an acute leukemia, usually acute myeloblastic leukemia. However, few cases of transformation into acute lymphoblastic leukemia (ALL) have been described. We present a case of refractory anemia that transformed into ALL two months after diagnosis and was successfully treated with conventional chemotherapy. Two years later a hyperfibrotic form of MDS was detected in the patient, that soon after terminated in acute megakaryoblastic leukemia. The course of MDS in the present case provides evidence that MDS can involve a pluripotent stem cell, presenting clonal evolution, documented by successive changes in its clinical and hematological features.