Acute erythroid leukemia

An unusual case of pure erythroid leukemia with normal karyotype and NPM1 mutation

Pure erythroid leukemia (PEL) is an extremely rare subtype of acute myeloid leukemia (AML). Although not specific, PEL is almost uniformly associated with complex karyotype and TP53 mutations. Given the rarity of the disease, our understanding of its cytogenetic and molecular features deems incomplete. We aim to complement existing literature by presenting an unusual case of PEL. The case is comprehensively worked up with multiple modalities. We present for the first time a case of PEL with unusual cytogenetic and molecular features: normal karyotype with absence of TP53 mutations and presence of NPM1 and NRAS mutations. This is a valuable addition to literature, expanding our understanding of molecular and cytogenetic spectra of PEL.

The Role of Epithelial-to-Mesenchymal Transition Transcription Factors (EMT-TFs) in Acute Myeloid Leukemia Progression

Acute myeloid leukemia (AML) is a diverse malignancy originating from myeloid progenitor cells, with significant genetic and clinical variability. Modern classification systems like those from the World Health Organization (WHO) and European LeukemiaNet use immunophenotyping, molecular genetics, and clinical features to categorize AML subtypes. This classification highlights crucial genetic markers such as FLT3, NPM1 mutations, and MLL-AF9 fusion, which are essential for prognosis and directing targeted therapies. The MLL-AF9 fusion protein is often linked with therapy-resistant AML, highlighting the risk of relapse due to standard chemotherapeutic regimes. In this sense, factors like the ZEB, SNAI, and TWIST gene families, known for their roles in epithelial-mesenchymal transition (EMT) and cancer metastasis, also regulate hematopoiesis and may serve as effective therapeutic targets in AML. These genes contribute to cell proliferation, differentiation, and extramedullary hematopoiesis, suggesting new possibilities for treatment. Advancing our understanding of the molecular mechanisms that promote AML, especially how the bone marrow microenvironment affects invasion and drug resistance, is crucial. This comprehensive insight into the molecular and environmental interactions in AML emphasizes the need for ongoing research and more effective treatments.

Acute Erythroid Leukemia: From Molecular Biology to Clinical Outcomes

Acute Erythroid Leukemia (AEL) is a rare and aggressive subtype of Acute Myeloid Leukemia (AML). In 2022, the World Health Organization (WHO) defined AEL as a biopsy with ≥30% proerythroblasts and erythroid precursors that account for ≥80% of cellularity. The International Consensus Classification refers to this neoplasm as "AML with mutated TP53". Classification entails ≥20% blasts in blood or bone marrow biopsy and a somatic TP53 mutation (VAF > 10%). This type of leukemia is typically associated with biallelic TP53 mutations and a complex karyotype, specifically 5q and 7q deletions. Transgenic mouse models have implicated several molecules in the pathogenesis of AEL, including transcriptional master regulator GATA1 (involved in erythroid differentiation), master oncogenes, and CDX4. Recent studies have also characterized AEL by epigenetic regulator mutations and transcriptome subgroups. AEL patients have overall poor clinical outcomes, mostly related to their poor response to the standard therapies, which include hypomethylating agents and intensive chemotherapy. Allogeneic bone marrow transplantation (AlloBMT) is the only potentially curative approach but requires deep remission, which is very challenging for these patients. Age, AlloBMT, and a history of antecedent myeloid neoplasms further affect the outcomes of these patients. In this review, we will summarize the diagnostic criteria of AEL, review the current insights into the biology of AEL, and describe the treatment options and outcomes of patients with this disease.

The Anti-Cancer Effect of Cinnamon Aqueous Extract: A Focus on Hematological Malignancies

Cinnamon is an evergreen and tropical plant of the family Lauraceae, growing particularly in Sri Lanka, whose aqueous extract has been tested in different studies to evaluate its possible use as an anti-cancer compound. Both in vitro and in vivo experiments seem to confirm that it acts on various cellular pathways, contributing to down-regulating the activity of molecules that stimulate the proliferation and survival of cells such as the transcription factors NF-KB and AP-1, COX-2, dihydrofolate reductase and pro-angiogenic substances such as VEGF, while up-regulating the function of immune cells against tumors, such as cytotoxic CD8+ T cells. In hematological malignancies, aqueous cinnamon extract has been studied in order to understand if it is possible to count on its help, alone or in combination with traditional drugs such as doxorubicin, to treat patients. The aim of our work is to investigate results from in vitro and in vivo studies about the possible anti-cancer effect of aqueous cinnamon extract in hematological malignancies and the different pathways involved in its action. The possibility of using cinnamon extract in clinical practice is discussed; even if its use could appear very interesting, more studies are necessary to clear the real potentiality of this substance in cancer.

To bi or not to bi: Acute erythroid leukemias and hematopoietic lineage choice

Acute erythroid leukemia (AEL) is an acute leukemia characterized by erythroid lineage transformation. The World Health Organization (WHO) 2008 classification recognized two subtypes of AEL: bilineage erythroleukemia (erythroid/myeloid leukemia) and pure erythroid leukemia. The erythroleukemia subtype was removed in the updated 2016 WHO classification, with about half of cases reclassified as myelodysplastic syndrome (MDS) and half as acute myeloid leukemia (AML). Diagnosis and classification are currently based on morphology using standard blast cutoffs, without integration of underlying genomic and other molecular features. Key outstanding questions are therefore whether AEL can be accurately diagnosed based solely on morphology or whether genetic or other molecular criteria should be included in its classification, and whether considering AEL as an entity distinct from AML and MDS is clinically relevant. We discuss recent work on the molecular basis of AEL, including the identification of mutations causative of AEL and of transcriptional and epigenetic features that can be used to distinguish AEL from MDS and nonerythroid AML, and the prognostic value of these molecular features.

Whole transcriptome sequencing and integrated network analysis elucidates the effects of 3,8-Di-O-methylellagic acid 2-O-glucoside derived from Sanguisorba offcinalis L., a novel differentiation inducer on erythroleukemia cells

Acute erythroid leukemia (AEL) is a rare and aggressive hematologic malignancy with no specific treatment. Sanguisorba officinalis L. (S. officinalis), a well-known traditional Chinese medicine, possesses potent anticancer activity. However, the active components of S. officinalis against AEL and the associated molecular mechanisms remain unknown. In this study, we predicted the anti-AML effect of S. officinalis based on network pharmacology. Through the identification of active components of S. officinalis, we found that 3,8-Di-O-methylellagic acid 2-O-glucoside (DMAG) not only significantly inhibited the proliferation of erythroleukemic cell line HEL, but also induced their differentiation to megakaryocytes. Furthermore, we demonstrated that DMAG could prolong the survival of AEL mice model. Whole-transcriptome sequencing was performed to elucidate the underlying molecular mechanisms associated with anti-AEL effect of DMAG. The results showed that the total of 68 miRNAs, 595 lncRNAs, 4030 mRNAs and 35 circRNAs were significantly differentially expressed during DMAG induced proliferation inhibition and differentiation of HEL cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the differentially expressed miRNAs, lncRNAs, mRNAs and circRNAs were mainly involved in metabolic, HIF-1, MAPK, Notch pathway and apoptosis. The co-expression networks showed that miR-23a-5p, miR-92a-1-5p, miR-146b and miR-760 regulatory networks were crucial for megakaryocyte differentiation induced by DMAG. In conclusion, our results suggest that DMAG, derived from S. officinalis might be a potent differentiation inducer of AEL cells and provide important information on the underlying mechanisms associated with its anti-AEL activity.

C/EBPα and GATA-2 Mutations Induce Bilineage Acute Erythroid Leukemia through Transformation of a Neomorphic Neutrophil-Erythroid Progenitor

Acute erythroid leukemia (AEL) commonly involves both myeloid and erythroid lineage transformation. However, the mutations that cause AEL and the cell(s) that sustain the bilineage leukemia phenotype remain unknown. We here show that combined biallelic Cebpa and Gata2 zinc finger-1 (ZnF1) mutations cooperatively induce bilineage AEL, and that the major leukemia-initiating cell (LIC) population has a neutrophil-monocyte progenitor (NMP) phenotype. In pre-leukemic NMPs Cebpa and Gata2 mutations synergize by increasing erythroid transcription factor (TF) expression and erythroid TF chromatin access, respectively, thereby installing ectopic erythroid potential. This erythroid-permissive chromatin conformation is retained in bilineage LICs. These results demonstrate that synergistic transcriptional and epigenetic reprogramming by leukemia-initiating mutations can generate neomorphic pre-leukemic progenitors, defining the lineage identity of the resulting leukemia.

Morphologic and immunophenotypic features of a case of acute monoblastic leukemia with unusual positivity for Glycophorin-A

Acute monoblastic leukemia (AMoL) is characterized by cells with highly undifferentiated morphology. Cytochemistry with non-specific esterases is negative in up to 20% of cases. Immunophenotyping by flow cytometry has an essential role in diagnosing such a subtype of leukemia and a multiparametric approach with a wide monoclonal antibody panel is necessary. We describe a case of AMoL with morphology resembling either plasma blasts or very immature erythroblasts. Diagnosis was made by alpha-naphtyl-acetate esterase staining and with immunophenotyping, which was made with a wide monoclonal antibody panel. Blasts were positive for monocytic markers. Most of leukemic cells, however, were positive for Glycophorin-A. The presence of Glycophorin-A, which is considered as a specific marker of the erythroid lineage, has never been reported previously in cases of AMoL. This peculiar immunophenotype might be interpreted as deriving from a common myelo-erythroid precursor undergone leukemic transformation.

Knockdown of Long Noncoding RNA Plasmacytoma Variant Translocation 1 with Antisense Locked Nucleic Acid GapmeRs Exerts Tumor-Suppressive Functions in Human Acute Erythroleukemia Cells Through Downregulation of C-MYC Expression

Objective: Acute erythroleukemia (AEL) is a subtype of acute myeloid leukemia (AML), with no specific treatment. Up- or downregulation of long noncoding RNAs (lncRNAs) is strongly associated with the formation and progression of many malignancies. Plasmacytoma variant translocation 1 (PVT1) is a significantly upregulated lncRNA in AML. Antisense locked nucleic acid (LNA) GapmeRs oligonucleotides are the novel tools for targeting lncRNAs. The purpose of the current study was to investigate the functional role of PVT1 antisense LNA GapmeRs on AEL cell line (KG-1). Materials and Methods: AEL cells were transfected with PVT1 antisense LNA GapmeRs at three different time points. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was accomplished to evaluate the PVT1 expression by PVT1 antisense LNA GapmeRs. The viability was evaluated by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay, and the apoptosis and necrosis were assessed by Annexin V/propidium iodide staining assay. The C-MYC expression level, the target gene of PVT1, was also quantified by qRT-PCR. Results: The results indicated that PVT1 inhibition could significantly decrease the viability of AEL cells, due to induction of apoptosis and necrosis, probably through the downregulation of C-MYC. Conclusions: Their findings suggest that the inhibition of lncRNA PVT1 could serve as a novel approach for controlling the proliferation of AEL cells and could open up a path for treatment of AEL.

Induction of apoptosis and necrosis in human acute erythroleukemia cells by inhibition of long non-coding RNA PVT1

Recent advances in molecular medicine have proposed new therapeutic strategies for cancer. One of the molecular research lines for the diagnosis and treatment of cancer is the use of long non-coding RNAs (LncRNAs) which are a class of non-coding RNA molecules longer than 200 base pairs in length that act as the key regulator of gene expression. Different aspects of cellular activities like cell growth, proliferation, differentiation, apoptosis and migration are regulated by lncRNAs. In various cancers, aberrant expression of lncRNAs has been reported. One of the lncRNAs that showed upregulation in human acute myeloid leukemia (AML) is lncRNA plasmacytoma variant translocation 1 (PVT1). Here, we performed blockage of lncRNA PVT1 in human acute erythroleukemia (AEL) cell line (KG1) using antisense LNA GapmeRs. Then, at different time points (24, 48 and 72 hours) after transfection, qRT‑real‑time PCR and AnnexinV/Propidium Iodide staining assay were performed. The data were processed using the ANOVA test. At all three time points, the ratio of apoptotic cells in the PVT1 antisense LNA GapmeRs treated group was higher than the other groups. The ratio of necrotic cells in the antisense LNA GapmeRs group was also higher than the other groups. These assessments show that inhibition of lncRNA PVT1 could significantly induce apoptosis and necrosis in KG1 cells. Our findings can be used in translational medicine for future investigation in acute erythroleukemia and treatment approach based on antisense therapy.

Re-evaluation of acute erythroid leukemia according to the 2016 WHO classification

In the recent update of WHO classification, the definition of myeloid neoplasms with erythroid predominance has been modified shifting the main criteria for calculating blast percentage from non-erythroid cells (NEC) to all nucleated marrow cells (ANC). Thus, the cases previously classified as erythroid/myeloid subtype of acute erythroid leukemia (AEL) based on the 2008 WHO will now be categorized either as myelodysplastic syndrome with excess blasts (MDS-EB) or acute myeloid leukemia, not otherwise specified (AML-NOS). However, the clinical significance of this new classification has not been demonstrated. Thus, we reviewed a leukemia database and reclassified 38 cases previously diagnosed as AEL, erythroid/myeloid subtype, with the consideration of 2016 revision criteria. Twenty seven (71%) of them had >20% blasts in NEC but less than 20% blasts in ANC, and 11 (29%) had >20% in both NEC and ANC. There was no significant difference in overall survivals (OS) among AEL, MDS-EB, and AML-NOS (non-erythroid predominance, NEP). However, AML with myelodysplasia-related changes showed significant shorter OS than AEL, MDS-EB and AML-NOS (NEP). Our results indicate that in myeloid neoplasm with erythroid predominance, patients with >20% blasts, of either NEC or ANC, share similar clinical laboratory features and survival outcomes with AML-NOS.

Clinical Outcomes of 217 Patients with Acute Erythroleukemia According to Treatment Type and Line: A Retrospective Multinational Study

Acute erythroleukemia (AEL) is a rare disease typically associated with a poor prognosis. The median survival ranges between 3-9 months from initial diagnosis. Hypomethylating agents (HMAs) have been shown to prolong survival in patients with myelodysplastic syndromes (MDS) and AML, but there is limited data of their efficacy in AEL. We collected data from 210 AEL patients treated at 28 international sites. Overall survival (OS) and PFS were estimated using the Kaplan-Meier method and the log-rank test was used for subgroup comparisons. Survival between treatment groups was compared using the Cox proportional hazards regression model. Eighty-eight patients were treated with HMAs, 44 front line, and 122 with intensive chemotherapy (ICT). ICT led to a higher overall response rate (complete or partial) compared to first-line HMA (72% vs. 46.2%, respectively; p ≤ 0.001), but similar progression-free survival (8.0 vs. 9.4 months; p = 0.342). Overall survival was similar for ICT vs. HMAs (10.5 vs. 13.7 months; p = 0.564), but patients with high-risk cytogenetics treated with HMA first-line lived longer (7.5 for ICT vs. 13.3 months; p = 0.039). Our results support the therapeutic value of HMA in AEL.

Pure erythroid leukemia

The category of acute erythroid leukemia was significantly revised in the recently published 2016 revision to the World Health Organization (WHO) classification of myeloid neoplasms. In the previous 2008 WHO classification, acute erythroid leukemia was categorized into two subtypes: erythroleukemia and pure erythroid leukemia (PEL), whereas in the 2016 WHO update, erythroleukemia was merged into myelodysplastic syndrome, and PEL becomes the only type of acute erythroid leukemia. PEL is a rare and aggressive form of acute leukemia whose biology remains poorly characterized. In this review, we discuss the clinicopathologic features, diagnosis, putative pathogenesis, and molecular biology of PEL, with an overview of novel concepts and future directions in this area.

Study of clinical, haematological and cytogenetic profile of patients with acute erythroid leukaemia

Background

Acute erythroid leukaemia (AEL) is a rare subtype of acute myeloid leukaemia (AML), constituting <5% of all the cases of AML. The World Health Organization (WHO) in 2001 classified AEL into two types: (1) erythroid/myeloid leukaemia which required ≥50% erythroid precursors with ≥20% of the non-erythroid cells to be myeloid blasts and (2) pure erythroleukemia (pEL) with ≥80% erythroblasts. The WHO 2008 classification kept these subcategories, but made erythroleukemia a diagnosis of exclusion. There are very few studies on the clinico haematological and cytogenetic profile of this disease, considering the rarity of its occurrence and poor prognosis.

Materials and methods

This study was done by retrospective analysis of data from 32 case files of patients diagnosed with AEL. Clinical details noted down were the demographic profile, peripheral blood smear details and bone marrow examination details: (1) blasts-erythroblasts and myeloblasts, (2) dysplasia in the cell lineages and (3) cytogenetic abnormalities.

Results

The most common presenting symptom was fever. Pancytopenia at presentation was seen in 81.25% of patients. Dysplasia was observed in bone marrow in 100% of erythroblasts and in 40% of myeloblasts in erythroid/myeloid subtype. In pure myeloid subtype, myeloid and megakaryocytic dysplasias were not obvious. Complex karyotype was noticed only in patients of pEL.

Conclusion

AEL is a rare group of heterogeneous diseases with many neoplastic and non-neoplastic conditions mimicking the diagnosis. The clinical presentation and cytogenetics are also non-specific, presenting additional challenges to the diagnosis.

Do Not Forget the Glycophorin A: An Unusual Case of Myeloid Sarcoma

Acute erythroid leukemia is rare, with isolated reports on presentation as an extramedullary tumor mass (myeloid sarcoma). We describe a case of pure erythroid leukemia presenting as an orbital mass in a 1-year, 9-month-old girl. This is only the second case described in a child. Tissue biopsy of the tumor mass showed medium-sized cells that were glycophorin A positive and negative with conventional myeloid markers. Flow cytometry, bone marrow aspirate, and trephine confirmed the diagnosis of pure erythroid leukemia.

Pure Erythroid Leukemia Mimicking Ewing Sarcoma/Primitive Neuroectodermal Tumor in an Infant

Pure erythroid leukemia (PEL) is a rare type of acute myeloid leukemia (AML) with a very aggressive clinical course. Presentation as a myeloid/erythroid sarcoma is exceedingly rare. We describe an infantile PEL presenting as a multifocal myeloid sarcoma, clinically and pathologically mimicking Ewing sarcoma/PNET family of tumors. The patient died 8 weeks after the initial presentation due to widespread disease. Our case shows that PEL needs to be considered in the differential diagnosis of small round blue cell tumors in infancy. A meticulous workup including immunohistochemistry, flow cytometry, molecular, and cytogenetic studies was required to reach the diagnosis.

Pure Erythroid Leukemia and Erythroblastic Sarcoma Evolving From Chronic Myeloid Neoplasms

OBJECTIVES

Pure erythroid leukemia (PEL) is an extremely rare entity that may, even more rarely, evolve from a preexisting chronic myeloid neoplasm (CMN); there is minimal literature regarding this latter phenomenon.

METHODS

We describe 14 patients with PEL that represented progression from a preexisting myelodysplastic syndrome (MDS, n = 8) or myeloproliferative neoplasm (MPN, n = 6), three of which manifested as erythroblastic sarcoma (EBS), a rare entity. These patients had a highly complex karyotype with prominent clonal evolution and a very aggressive clinical course.

RESULTS

Patients with PEL from MDS showed a more rapid progression time to PEL and had lower platelet counts compared with PEL from MPN. No other significant differences were found between the two groups.

CONCLUSIONS

These data represent the largest cohort of patients with PEL and an antecedent CMN, as well as the largest series of EBS reported to date, and underscore the unique morphologic, cytogenetic, immunophenotypic, and clinical features of this uncommon entity.

Killing the hypnozoite--drug discovery approaches to prevent relapse in Plasmodium vivax

The eradication of malaria will only be possible if effective, well-tolerated medicines kill hypnozoites in vivax and ovale malaria, and thus prevent relapses in patients. Despite progress in the 8-aminoquinoline series, with tafenoquine in Phase III showing clear benefits over primaquine, the drug discovery challenge to identify hypnozoiticidal or hypnozoite-activating compounds has been hampered by the dearth of biological tools and assays, which in turn has been limited by the immense scientific and logistical challenges associated with accessing relevant human tissue and sporozoites. This review summarises the existing drug discovery series and approaches concerning the goal to block relapse.

Complex karyotype with novel translocation in pure erythroid leukemia patient

Pure erythroid leukemia (PEL) is rare hematopoietic neoplasm characterized by uncontrolled proliferation of immature erythroid precursors - mainly abnormal proery-throblasts - comprising at least 80% of bone marrow cells. In this paper, I present a case of 48 years old patient, who presented with pancytopenia and circulating erythroblast in peripheral blood after long history of alcohol abuse. Bone marrow examination revealed hypercellular marrow which is markedly infiltrated with immature erythroid precursors. An expanded panel of immunophenotyping markers has confirmed the diagnosis of PEL. Cytogenetics analysis detected a complex karyotype with multiple chromosomal abnormalities and a novel translocation, t(8;9) (p11.2;q12), which has not been reported in acute myeloid leukemia (AML) in the past. The patient was treated with standard AML chemotherapy but he did not show an optimal response and passed away. An updated and short review about various aspects of PEL has been made with special focus on immunophenotyping and genetic studies.

Erythroleukemia and Its Differential Diagnosis

Acute erythroid leukemias encompass 2 main subtypes: acute erythroleukemia (erythroid/myeloid subtype) and pure erythroid leukemia. This article reviews the main clinicopathologic features of the acute erythroid leukemias and the criteria used to diagnose them. In this article, the differential diagnosis between acute erythroid leukemias and their mimics is discussed and helpful morphologic clues and diagnostic tests that help arrive at the correct diagnosis are provided. The appropriate application of diagnostic criteria, including ancillary testing, such as immunophenotyping, cytogenetics, and molecular genetic testing, is essential to categorize bone marrow erythroid proliferations.

Transposon mutagenesis reveals cooperation of ETS family transcription factors with signaling pathways in erythro-megakaryocytic leukemia

To define genetic lesions driving leukemia, we targeted cre-dependent Sleeping Beauty (SB) transposon mutagenesis to the blood-forming system using a hematopoietic-selective vav 1 oncogene (vav1) promoter. Leukemias of diverse lineages ensued, most commonly lymphoid leukemia and erythroleukemia. The inclusion of a transgenic allele of Janus kinase 2 (JAK2)V617F resulted in acceleration of transposon-driven disease and strong selection for erythroleukemic pathology with transformation of bipotential erythro-megakaryocytic cells. The genes encoding the E-twenty-six (ETS) transcription factors Ets related gene (Erg) and Ets1 were the most common sites for transposon insertion in SB-induced JAK2V617F-positive erythroleukemias, present in 87.5% and 65%, respectively, of independent leukemias examined. The role of activated Erg was validated by reproducing erythroleukemic pathology in mice transplanted with fetal liver cells expressing translocated in liposarcoma (TLS)-ERG, an activated form of ERG found in human leukemia. Via application of SB mutagenesis to TLS-ERG-induced erythroid transformation, we identified multiple loci as likely collaborators with activation of Erg. Jak2 was identified as a common transposon insertion site in TLS-ERG-induced disease, strongly validating the cooperation between JAK2V617F and transposon insertion at the Erg locus in the JAK2V617F-positive leukemias. Moreover, loci expressing other regulators of signal transduction pathways were conspicuous among the common transposon insertion sites in TLS-ERG-driven leukemia, suggesting that a key mechanism in erythroleukemia may be the collaboration of lesions disturbing erythroid maturation, most notably in genes of the ETS family, with mutations that reduce dependence on exogenous signals.

Two cases of acute erythroid leukemia presenting with marked macrocytic anemia, reticulocytosis and hemolysis

Case 1. The laboratory findings of a hematological analysis of a 53-year-old woman with palpitations and dyspnea revealed the following: red blood cell (RBC) count: 9.4×10(5)/μL with 60.0‰ reticulocytes; Hb: 3.7 g/dL; mean corpuscular volume (MCV): 124.5 fL; white blood cell (WBC) count: 2,800/μL with 10.0% myeloblasts. Case 2. Similarly, a 42-year-old man with dizziness had a RBC count of 1.63×10(6)/μL with 24.0% reticulocytes, an Hb level of 6.0 g/dL, an MCV of 120.2 fL and a WBC count of 3,100/μL with 4.0% myeloblasts. Bone marrow aspirates in both patients confirmed a diagnosis of acute erythroid leukemia (AEL), which can present as marked macrocytic anemia with an MCV in excess of 120 fL and hemolysis.

Acute myeloid leukemia (AML) with erythroid predominance exhibits clinical and molecular characteristics that differ from other types of AML

The clinical importance of erythroid predominance in bone marrow of patients with acute myeloid leukemia (AML) is controversial. These cases represent a heterogeneous group of diseases that historically have been classified into different categories. We studied 313 AML patients and specifically compared the clinical, cytogenetic, and molecular features of cases of AML with erythroid predominance, arbitrarily defined as ≥50% erythroid precursors, to AML cases without erythroid predominance. We also assessed 51 patients with a high-grade myelodysplastic syndrome (MDS), refractory anemia with excess blasts (RAEB). All neoplasms were classified according to the World Health Organization classification. With the exception of therapy-related AML/MDS, the presence of erythroid predominance in variously classified categories of AML was associated with a survival advantage. In addition, AML with erythroid predominance had a lower frequency of cytogenetic abnormalities as well as a lower frequency of mutations involving NPM1, NRAS and FLT3 as compared with AML without erythroid predominance. We conclude that the clinical, cytogenetic, and molecular features of AML with erythroid predominance in the non-therapy-related setting are much closer to those of a high-grade myelodysplastic syndrome than they are to other types of AML.

Pure erythroid leukemia following precursor B-cell lymphoblastic leukemia

Therapy-related acute myeloid leukemia is an unfortunate sequel to current multimodal intensive chemotherapy. The patient described was diagnosed with pure erythroleukemia, AML-M6b, during therapy for precursor B-cell acute lymphoblastic leukemia. To the best of our knowledge, this is the first report of this unusual association.

Acute erythroid leukemia: autopsy report of a rare disease

Acute erythroid leukemia (AEL) is a rare subtype of acute myeloid leukemia (AML), characterized by predominant erythroid proliferation. The 2008 World Health Organization (WHO) classification of AML defined two AEL subtypes: erythroleukaemia (EL), in which erythroid precursors account for 50% or more of all nucleated bone marrow cells and myeloblasts account for 20% or more of the nonerythroid cell population; and pure erythroid leukemia (PEL), in which erythroid precursors account for 80% or more of all nucleated bone marrow cells. We report the case of an elderly female patient with wasting syndrome and pancytopenia without evidence of blasts in peripheral blood. A diagnosis of PEL was established on the basis of bone marrow biopsy findings. The patient died on postadmission day 20, and an autopsy was performed. We reclassified the disease as EL on the basis of the autopsy findings, which included myeloblasts accounting for more than 20% of the nonerythroid cells in the bone marrow, as well as leukemic infiltration and myeloid metaplasia in solid organs, such as the liver, spleen, kidneys, adrenal glands, and abdominal lymph nodes. A rare disease, AEL accounts for less than 5% of all AMLs and is practically a diagnosis of exclusion. Autopsy reports of AEL are extremely rare in the literature. We demonstrate that in the case reported here, leukemia cells tended to infiltrate solid organs with myeloid metaplasia. Our findings also show that a larger neoplastic bone marrow sample is crucial to the correct diagnosis of EL, which is based on morphological and quantitative criteria.

State of the art in myeloid sarcoma

INTRODUCTION

Myeloid sarcomas are extramedullary lesions composed of myeloid lineage blasts that typically form tumorous masses and may precede, follow, or occur in the absence of systemic acute myeloid leukemia. They most commonly involve the skin and soft tissues, lymph nodes, and gastrointestinal tract and are particularly challenging to diagnose in patients without an antecedent history of acute myeloid leukemia.

METHODS

We conducted a search of the English language medical literature for recent studies of interest to individuals involved in the diagnosis of myeloid sarcoma.

RESULTS

The differential diagnosis includes non-Hodgkin lymphoma, blastic plasmacytoid dendritic cell neoplasm, histiocytic sarcoma, melanoma, carcinoma, and (in children) small round blue cell tumors. The sensitivity and specificity of immunohistochemical markers must be considered when evaluating a suspected case of myeloid sarcoma. A high percentage of tested cases have cytogenetic abnormalities.

CONCLUSION

A minimal panel of immunohistochemical markers should include anti-CD43 or anti-lysozyme as a lack of immunoreactivity for either of these sensitive markers would be inconsistent with a diagnosis of myeloid sarcoma. Use of more specific markers of myeloid disease, such as CD33, myeloperoxidase, CD34 and CD117 is necessary to establish the diagnosis. Other antibodies may be added depending on the differential diagnosis. Identification of acute myeloid leukemia-associated genetic lesions may be helpful in arriving at the correct diagnosis.