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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. [ABSTRACT FROM AUTHOR]

Simple Summary: Pure erythroid leukemia (PEL), a rare subtype of acute myeloid leukemia (AML), is characterized by the proliferation of malignant erythroid precursors. To understand the status of PEL at the population level, a retrospective analysis was conducted using the Surveillance Epidemiology and End Results (SEER) database from 2000 to 2019. The study included 968 patients with a confirmed diagnosis of PEL, with a median age of 68 years and a higher proportion of males (62%). Among the patients, 62.5% received chemotherapy. The overall survival (OS) rates varied significantly based on age, with better outcomes seen in younger age groups. Chemotherapy was associated with improved OS both in adults and children. However, there were no significant differences in OS based on sex, race, ethnicity, or median household income. Over the two decades of the study, there was no notable improvement in OS, indicating poor outcomes with current chemotherapeutic agents. The study underscores the urgent need for investigational agents that are capable of inducing remission. Background: Acute erythroid leukemia (AEL), also known as pure erythroid leukemia, is a rare subtype of acute myeloid leukemia (AML) characterized by the proliferation of malignant erythroid precursors. Outcome data at the population level are scarce. Methods: We performed a retrospective analysis of the Surveillance Epidemiology and End Results (SEER) database. All cases with a histologically confirmed diagnosis of acute (pure) erythroid leukemia during the period of 2000–2019 were included in the study. The Kaplan–Meier method was used to perform survival analysis. The significance of differences between overall survival (OS) was analyzed using the log-rank test. Results: In total, 968 patients were included in the study. The median age was 68 years (range 0–95), 62% of patients were males, and 62.5% (n = 605) were treated with chemotherapy. The median OS for <18, 18–49, 50–64, 65–79 and 80+ age groups was 69, 18, 8, 3 and 1 month, respectively (p < 0.0001). Patients who received chemotherapy had significantly improved OS compared to patients who did not, among both adults (p < 0.0001) and children (p = 0.004). There were no significant differences in OS based on sex, race, ethnicity and median household income. Median OS for adults diagnosed in 2000–2004, 2005–2009, 2010–2014, 2015–2019 was 4, 6, 6 and 3 months, respectively, with no significant differences in OS between these groups. Conclusion: AEL occurs in all age groups but is most common in the elderly. Outcomes are poor with current chemotherapeutic agents, with no improvement in the last two decades. This study stresses the urgent need for investigational agents. [ABSTRACT FROM AUTHOR]

Acute erythroid leukemia treatment is associated with poor survival. The most common treatments are intensive chemotherapy regimens and hypomethylating agents. Choice of preferred therapy is complex, and data are conflicting on the optimal regimen. The definition of AEL has also shifted with time but the impacts of these changes on survival reporting are largely unknown.We designed a single-center, retrospective review of patients meeting the 2001 World Health Organization definition of acute erythroid leukemia. Patients were treated with an intensive chemotherapy or a hypomethylating agent regimen. The primary outcome was overall survival.Most patients were older with complex karyotypes. Median overall survival did not differ between treatment groups. When survival was stratified by WHO 2022 diagnosis, patients meeting MDS criteria had notably increased survival outcomes while patients still meeting the definition of AEL did poorly regardless of induction regimen.Treatment of acute erythroid leukemia remains complex with poor survival outcomes. [ABSTRACT FROM AUTHOR]

Pure erythroid leukemia (PEL) is an extremely rare type of acute myeloid leukemia (AML), accounting for fewer than 1% of all AML cases. A 72-year-old man presented with severe fatigue. His bone marrow aspiration contained myeloperoxidase negative abnormal cells that were aggregating and depicting epithelial adhesion, suggesting the possibility of solid tumor metastasis. His general condition deteriorated during medical diagnosis, and he died soon after starting chemotherapy. PEL appeared to be the definitive diagnosis after evaluating the histopathological findings, which were obtained after his death. With atypical morphological features, immunophenotypic and karyotypic approaches must be integrated for PEL assessment.

We present a very rare case of pure erythroid leukemia arising in a young patient with sickle cell disease being treated with hydroxyurea for almost 5 years. Diagnosing and managing this rare condition has been a challenge and the majority of patients with pure erythroid leukemia have a very poor prognosis with survival in months despite treatment. This form of leukemia could be therapy related and in our case, hydroxyurea may have been responsible for the development of this aggressive condition.

Pure erythroid leukemia (AML-M6) is a rare variant of acute myeloid leukemia (AML) with predominant erythroid lineage proliferation. The incidence of AIDS defining cancers including Kaposi sarcoma and non-Hodgkins lymphoma are on declining trends due to effective use of HAART (Highly Active Antiretroviral Therapy). Correspondingly, there have been increasing cases of leukemia in persons living with HIV. Our case is a 43 years old male living with HIV who was admitted with high grade fever and mucosal bleeds. On examination, he had periorbital swelling and ecchymosis with hepatosplenomegaly. The laboratory investigations revealed bicytopenia with high ferritin, low fibrinogen and hypertriglyceridemia. A diagnosis of hemophagocytic lymphohistiocytosis (HLH) with H score of 222 was made. Bone marrow examination revealed hypercellular marrow with more than 80% cells of erythroid lineage with 47% proerythroblasts. Suggesting pure erythroid leukemia (AML-M6). This diagnosis with secondary HLH carries a very poor prognosis in persons living with HIV., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Chronic myeloid leukemia (CML), a myeloproliferative neoplasm defined by the presence of the BCR-ABL1 oncogene created by the reciprocal translocation t(9;22)(q34.1;q11.2), can often be controlled by medications that inhibit this constitutive tyrosine kinase. However, if these therapies fail, the disease may progress to a form resembling an acute leukemia. While most of these CML 'blast crises' are characterized by blasts with a myeloid (granulocytic) or lymphoid lineage, these blasts may rarely be predominantly erythroid. Cases of CML erythroid blast crises have been reported; however, secondary pure erythroid leukemia arising from a CML blast crisis has only been definitively reported once before. We report the second definitive case of pure erythroid leukemia with the t(9;22)(q34.1;q11.2) presenting as a CML blast crisis and characterize the morphologic, immunophenotypic, flow cytometric, cytogenetic, and molecular findings. [ABSTRACT FROM AUTHOR]

Objectives: Pure erythroid leukemia (PEL) is exceptionally rare in the pediatric setting. Four pediatric PEL cases with t(1;16)(p31;q24) NFIA-CBFA2T3 were reported previously. We present a case of an infant with PEL presenting with erythroblastic sarcoma and harboring a novel t(1;8)(p31.3;q21.3) NFIA-RUNX1T1 fusion detected by RNA sequencing and conventional karyotype.Methods: Bone marrow (BM) and abdominal mass biopsies from the patient were evaluated with extensive immunohistochemical, flow cytometric, cytogenetic, and molecular studies.Results: The patient was a female infant who presented between 2 and 5 months of age with cytopenias and an enlarging abdominal mass. Blasts in the BM and abdominal mass expressed CD71 and CD117 with focal expression of CD43, E-cadherin, epithelial membrane antigen, and hemoglobin A. They were negative for additional myeloid, lymphoid, and nonhematolymphoid markers. These findings were most consistent with PEL and erythroblastic sarcoma. RNA sequencing revealed the novel NFIA-RUNX1T1 fusion.Conclusions: Along with the previously reported PELs with NFIA-CBFA2T3 fusions, we describe a subset of PELs that occur in children, that frequently display extramedullary disease, and that harbor rearrangements of NFIA with core binding factor genes. We hypothesize that, together, these cases represent a rare but distinct clinicopathologic group of pediatric PELs with recurrent genetic abnormality. [ABSTRACT FROM AUTHOR]

Myeloid/lymphoid neoplasms with FGFR1 rearrangement (MLN-FGFR1) comprise a heterogeneous group of neoplasms that can present as a myeloproliferative neoplasm, a myelodysplastic/myeloproliferative neoplasm, acute myeloid leukemia, T or B lymphoblastic leukemia/lymphoma, or mixed phenotype acute leukemia. The overall outcome of these neoplasms is poor, and these patients often show cytogenetic evolution with gain of additional chromosomal abnormalities leading to transformation to acute leukemia. Pure erythroid leukemia and erythroblastic sarcoma evolving from a preexisting chronic myeloid neoplasm have rarely been described; however, this has not been reported in MLN-FGFR1. Herein we describe a biopsy-proven chronic myeloid neoplasm with FGFR1 rearrangement with transformation to erythroblastic sarcoma presenting as a pleural effusion. [ABSTRACT FROM AUTHOR]

Leukemic transformation in Polycythemia Vera (PV) is described as a rare and late event, less common than primary myelofibrosis (PMF). Blast phase in PV (PV-BP) develops at a median time of 12.8 years from diagnosis which implies a long-lasting exposure to myelosuppressive agents. Acute megakaryocytic leukemia (FAB M7) and acute myelomonocytic leukemia (FAB M4) are the common morphologic types described in blast phase of myeloproliferative neoplasms (MPN). Here we report a case of a 61 year old male who progressed to blast phase within three years of diagnosis of PV and was on cytoreduction with hydroxyurea. The leukemic transformation occurred in the form of pure erythroid leukemia (FAB M6) and was not preceded by a phase of documented post PV myelofibrosis (post PV- MF). The unusual features in this case include the short period from initial diagnosis to leukemic transformation and the uncommon morphologic subtype.

We present a very rare case of pure erythroid leukemia arising in a young patient with sickle cell disease being treated with hydroxyurea for almost 5 years. Diagnosing and managing this rare condition has been a challenge and the majority of patients with pure erythroid leukemia have a very poor prognosis with survival in months despite treatment. This form of leukemia could be therapy related and in our case, hydroxyurea may have been responsible for the development of this aggressive condition. [ABSTRACT FROM AUTHOR]

Abstract Pure erythroid leukemia is a rare and aggressive form of acute leukemia with a deleterious clinical course. It is of erythroid lineage without myeloblastic component, representing >80% of marrow cellularity, with ≥30% proerythroblasts.

Abstract Pure erythroid leukemia is an aggressive form of acute leukemia, presenting with pancytopenia. It is defined as a neoplasm of erythroid lineage without a significant myeloblastic component, representing >80% of marrow, with 30% or more proerythroblasts. The disease has a rapid clinical course with median survival of only 3 months.

Acute erythroleukemia is a rare form of acute myeloid leukemia recognized by its distinct phenotypic attribute of erythroblastic proliferation. After a century of its descriptive history, many diagnostic, prognostic, and therapeutic implications relating to this unique leukemia subset remain uncertain. The rarity of the disease and the simultaneous involvement of its associated myeloid compartment have complicated in vitro studies of human erythroleukemia cell lines. Although murine and cell line erythroleukemia models have provided valuable insights into pathophysiology, translation of these concepts into treatment are not forthcoming. Integration of knowledge gained through a careful study of these models with more recent data emerging from molecular characterization will help elucidate key mechanistic pathways and provide a much needed framework that accounts for erythroid lineage-specific attributes. In this article, we discuss the evolving diagnostic concept of erythroleukemia, translational aspects of its pathophysiology, and promising therapeutic targets through an appraisal of the current literature. [ABSTRACT FROM AUTHOR]

Congenital pure erythroid leukemia is exceedingly rare and poses a diagnostic challenge. We report an atypical case of congenital pure erythroid leukemia that did not express typical erythroid markers. The patient presented with a high white blood cell count with blastic cells at birth. Although flow cytometric analyses of peripheral blood and bone marrow showed a large CD45-negative cell population, we did not identify any evidence of monoclonality. While the circulating blasts decreased with only supportive care, hepatomegaly with multiple nodules was accompanied by liver failure, disseminated intravascular coagulation, and development of hemophagocytic lymphohistiocytosis. Pathological examination of the liver biopsy specimen revealed a small round cell tumor that was negative for nearly all hematopoietic cell markers, including classical erythroid cell markers, and positive for CD43, CD71, and E-cadherin, an early erythroid marker epithelial calcium-dependent adhesion protein, suggesting that these tumor cells originated from an immature erythroblast. We found high β-catenin and c-Myc protein expression, which were not previously described in pure erythroid leukemia. Cytosine arabinoside temporarily alleviated clinical symptoms; however, the patient died of progressive disease at 8 months of age. This case indicates that E-cadherin is useful for diagnosing pure erythroid leukemia, even in immature cases. [ABSTRACT FROM AUTHOR]

Aims Pure erythroid leukaemia (PEL) is an extremely rare and aggressive subtype of acute myeloid leukaemia defined by the World Health Organization (WHO) as a neoplastic proliferation of immature cells committed exclusively to the erythroid lineage, comprising >80% of bone marrow cells and not meeting the criteria of other well-defined myeloid neoplasms. The aim of this study was to describe the clinicopathological features of acute leukaemias with a pure erythroid phenotype (ALPEP) irrespective of their WHO classification and to determine if ALPEP represents a distinct clinicopathological entity. Methods and results We identified seven cases of ALPEP, in which immature cells fulfilled WHO morphological and immunophenotypical criteria for PEL. All patients except one were male, with a median age of 60 years. Three cases represented de novo PEL, three were therapy-related myeloid neoplasms and one was a blast phase of a myeloproliferative neoplasm. Extensive tumour necrosis was present in five cases (71%). Five cases with available modal karyotypes all demonstrated a complex karyotype involving the TP53 gene locus, with three cases (60%) also showing a monosomy 5 or deletion 5q and additional material on chromosome 19q13. All patients died of their disease, with a mean overall survival of 189 and 64.7 days in cases without and with necrosis on the initial biopsy, respectively. Conclusions We describe previously unreported but relatively common findings of extensive tumour necrosis and recurring cytogenetic abnormalities in ALPEP. Our findings suggest strongly that ALPEP represents a distinct clinicopathological entity regardless of its WHO classification. [ABSTRACT FROM AUTHOR]

Objectives: GATA binding factor 1 (GATA1) is a transcription factor essential for erythromegakaryocytic differentiation. Given its function in lineage specification, we sought to evaluate the immunohistochemical profile of GATA1 in normal marrow and acute leukemia and assess the use of GATA1 as a specific erythromegakaryocytic immunohistochemical marker.Methods: Immunohistochemical studies for GATA1 expression were performed on bone marrow biopsy specimens to define its role in the evaluation of acute leukemia and other hematologic disorders.Results: In normal marrows, intense nuclear reactivity is seen in immature erythroid precursors and megakaryocytes. Weak to moderate nuclear positivity is seen in eosinophils and mast cells. In marrows involved by acute leukemia, blasts of pure erythroleukemia and acute megakaryoblastic leukemia exhibit intense nuclear GATA1 positivity, while blasts of acute myeloid leukemia of other categories are negative. GATA1 is also absent in the blasts of acute lymphoblastic leukemia/lymphoma and in the neoplastic cells of metastatic carcinoma and plasma cell neoplasms.Conclusions: Intense GATA1 nuclear expression is a sensitive and specific marker for cells of erythroid and megakaryocytic lineages and is an excellent marker for neoplastic cells of pure erythroleukemia and acute megakaryoblastic leukemia. [ABSTRACT FROM AUTHOR]

Background: We present a case of focal lymphoblastic transformation to erythroid leukemia following acute myeloblastic transformation in a patient with chronic myelogenous leukemia (CML) and discuss its mechanism of occurrence and development., Case Summary: The presence of the Philadelphia (Ph) chromosome was identified through karyotype analysis, while the BCR-ABL fusion gene was detected using quantitative real-time polymerase chain reaction of the peripheral blood sample. Fluorescence in situ hybridization was used to detect the expression of the BCR-ABL gene in the lymphoma. Antigen expression and gene mutations in the primitive cells were detected by flow cytometry. The analysis confirmed the presence of CML along with focal lymphoblastic transformation to erythroid leukemia. Additionally, the patient was found to have secondary erythroid leukemia, along with multiple new gene mutations and abnormalities in complex karyotypes of chromosomes., Conclusion: Our findings suggest a possible molecular basis for the focal lymphoblastic transformation secondary to myeloblastic transformation in patients with CML., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

A 62-year-old male patient presented with malaise and severe macrocytic anemia. Computed tomography revealed an osteolytic lesion in the left iliac bone. Bone marrow examination revealed that 90% of erythroblasts were large with periodic acid-Schiff (PAS)-positive staining while flow cytometry and immunostaining revealed CD71 (+), GP-A (+), p53 (+), CD117 (+), and CD34 (-) results, indicating pure erythroid leukemia (PEL) diagnosis. A needle biopsy of the osteolytic lesion revealed the same characteristics as PEL. Azacitidine therapy was administered as the first-line treatment, and his general condition temporarily improved. However, PEL quickly deteriorated, and he died 42 days of hospitalization after initial admission. PEL is an extremely rare form of acute myeloid leukemia (AML) and has presented cytogenetic characteristics in addition to the TP53 mutation. Other AML treatment is used because a standard treatment method is unavailable. However, the prognosis is extremely poor. Furthermore, few cases of concurrent bone lesions are reported globally, and more cases must be accumulated and analyzed., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Okazaki et al.)

Pure erythroid leukemia (PEL), occurring after exposure to cytotoxic treatments for solid tumors, is an extremely rare disorder of which only very few cases have been reported until now. A 64-year-old woman, who had received multiple courses of chemoradiotherapy and endocrine agents, was diagnosed as having a therapy-related myelodysplastic syndrome (t-MDS) with erythroid predominance and hypodiploid complex abnormalities sixteen years after the initial diagnosis of breast cancer; the patient experienced several recurrences and a very complicated clinical course. t-MDS rapidly evolved into PEL and the patient died of progressive disease. Our observation confirmed that PEL may arise as therapy myeloid neoplasm and that this uncommon aggressive disorder portrays a very poor outcome.

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Objectives: At the 2013 Society for Hematopathology/ European Association for Hematopathology Workshop, 36 cases were submitted to the session that covered acute erythroid leukemia (AEL), acute megakaryoblastic leukemia (AMKL), and reactive mimics. Methods: Cases were reviewed by the session chairs and workshop panel to reach a consensus diagnosis. Results: For acute erythroleukemia, erythroid/myeloid type, discussion acknowledged overlapping features between AEL and myelodysplastic syndromes. Cases submitted as pure erythroid leukemia had distinctive morphology and immunophenotype, complex karyotypes, and aggressive clinical behavior, illustrating certain diagnostic features not currently captured by the current World Health Organization (WHO) definition. In Down syndrome, there were striking similarities between transient abnormal myelopoiesis and AMKL. Most cases of AMKL in adults would be classified as acute myeloid leukemia with myelodysplasia-related changes according to the WHO classification, but this approach deemphasizes their unique clinical, morphologic, and immunophenotypic features. Conclusions: The broad spectrum of cases illustrated the difficulties and complex issues involved in establishing a diagnosis of these entities and the need for better disease definitions. [ABSTRACT FROM AUTHOR]

Acute erythroid leukemia, also known as acute myeloid leukemia-M6, may be associated with previous chemotherapy or immunosuppressive therapy. For 10 years, a 69-year-old Japanese female patient with pure erythroid leukemia (or acute myeloid leukemia-M6b) was treated for polymyositis with 50-100 mg/day azathioprine. She complained of dyspnea with low-grade fever and was diagnosed as having pure erythroid leukemia. Chromosomal analysis revealed a complex karyotype abnormality, with the deletion of 5q, -6, -7 and addition of 11q13. No morphological myelodysplastic changes were observed in her bone marrow cells. In this study, azathioprine accumulation was considered to be associated with the patient's leukemogenesis. [ABSTRACT FROM AUTHOR]

Pure erythroid leukemia (PEL) is rare hematopoietic neoplasm characterized by uncontrolled proliferation of immature erythroid precursors - mainly abnormal proerythroblasts - 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. [ABSTRACT FROM AUTHOR]

Pure erythroid leukemia (PEL) is a rare acute leukemia with a dismal prognosis. TP53 mutations are a dominant feature of PEL, but the characteristics of TP53 alterations in PEL without prior exposure to cytotoxic therapy (d-PEL) or with such exposure (t-PEL) is unknown. We studied 25 patients with TP53 -mutated PEL including 16 d-PEL and 9 t-PEL. Both groups had comparable clinical findings and overall survival. The TP53 mutation, commonly missense, was present in the dominant clone in all cases. In the d-PEL group, 10/16 (62.5%) had one TP53 mutation compared to 8/9 (89%) patients in the t-PEL group. In the d-PEL group, 9/16 (56.2%) patients had hotspot mutations compared to 2 (22.2%) patients in the t-PEL group. Notably, monosomy 17 or del(17p) were less common in the d-PEL group (26.6%) compared to the t-PEL group (71.4%), underscoring distinctive TP53 alterations in d-PEL versus t-PEL, possibly reflecting different fitness advantages. • TP53 mutations are a dominant feature of PEL. • De novo and therapy-related PEL have different patterns of TP53 alterations. • PEL arising de novo has more combinations of hotspot mutations and an intact chromosome 17. • Monosomy 17 or del(17p) are more common in PEL arising post cytotoxic therapy. [ABSTRACT FROM AUTHOR]

Background: The immunophenotype of pure erythroid leukemia (PEL) as determined by flow cytometry immunophenotypic analysis is not well characterized. The immunophenotypic difference between PEL and reactive conditions is under-explored., Methods: We assessed and compared the immunophenotype of 24 PEL cases and 28 reactive cases containing early erythroid precursors by flow cytometry., Results: The neoplastic erythroid cells in all PEL cases were positive for CD36 and CD71. CD45 was also positive in all cases, but the expression level was often dimmer than granulocytes. CD117 expression ranged from partial to uniform, and CD235a was often only positive in the CD117-dim to negative cells, corresponding to more differentiated subset. PEL cases frequently (87%) showed decreased or negative CD38 expression, contrasting to reactive early erythroid precursors that showed bright CD38 (p < 0.0001). CD7 (25%) and CD13 (29%) aberrant expressions were only observed in PEL but not in the reactive erythroid cells. Normal early erythroid precursors in all reactive bone marrows showed partial expression of CD4; In contrast, aberrant CD4 expression was detected in 71% PEL cases, either uniformly positive (50%) or completely negative (21%). While normal/reactive bone marrows almost always contained a small subset of CD34-positive early erythroid precursors, the neoplastic pronormoblasts in all PEL cases were CD34 negative. Although not increased in number, CD34-positive myeloblasts were frequently detected in PEL and demonstrated an aberrant immunophenotype in 90% PEL cases., Conclusions: PEL shows a distinctive immunophenotype which can be distinguished from reactive erythroid precursors by flow cytometry immunophenotyping., (© 2022 International Clinical Cytometry Society.)

A 6.5-year-old, intact male Cocker Spaniel dog was referred with a history of depression and anorexia of 1-week duration. Mucosal pallor was prominent on physical examination. Complete blood cell count revealed pancytopenia and occasional blast cells. Bone marrow aspirate cytology indicated that individual particles were composed of approximately 60% hematopoietic cells and a monomorphic population of blast cells with perfectly round nuclei, consistent paranuclear clearing, and deeply basophilic cytoplasm devoid of granules dominating the marrow fields. The granulocytic lineage was severely decreased with a granulocytic-to-erythroid ratio of 0.15 and a blast cell percentage of at least 70% of all nucleated cells; the myeloblasts and monoblasts composed <5% of nonerythroid cells. Bone marrow cytology slides were submitted for immunocytochemical immunophenotyping using antibodies to myeloperoxidase, cluster of differentiation (CD)3, CD79a, CD11b, CD45, and CD34. The neoplastic cells did not express any of the antigens assessed. The combination of light microscopic cytomorphology and the immunophenotype were strongly suggestive of pure erythroid leukemia. [ABSTRACT FROM PUBLISHER]

Summary: Pure erythroid leukemia is a rare subtype of acute erythroid leukemia that is characterized by a predominant erythroid population, and erythroblastic sarcoma has not yet been described in the English literature. Here, we report a first case of erythroblastic sarcoma that presented as bilateral ovarian masses in a 3 ½–month-old infant girl with pure erythroid leukemia. Bone marrow aspirate and biopsy showed that the marrow was completely replaced by large-sized blasts consistent with erythroblasts. Immunophenotypically, both the tumor cells from the ovarian mass and bone marrow blasts were positive for CD117, glycophorin A, and hemoglobin A, demonstrating erythroid differentiation. Reverse transcriptase polymerase chain reaction showed that the tumor cells from ovarian mass expressed hemoglobin F and α1 spectrin, confirming their erythroid lineage. Conventional karyotype of the bone marrow aspirates revealed del(6)(q23q25) and trisomy 7 in all 21 cells examined. Fluorescence in situ hybridization of the ovarian mass demonstrated loss of c-myeloblastosis viral oncogene (C-MYB) at 6q23 locus in 41% of the cells, and deletion of chromosome 7 and 7q in 37% and 66% of cells, respectively. Taken together, we showed, for the first time, that pure erythroid leukemia presented as a myeloid sarcoma in the form of ovarian masses. [Copyright &y& Elsevier]