Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review

Abstract Introduction The RAM immunophenotype (IP) in acute myeloid leukemia (AML) is defined by blasts with bright CD56 and weak‐to‐negative CD45, HLA‐DR, and CD38 expression. A RAM IP predominantly presents in infants who have “standard‐risk disease” under current criteria but, when treated accord...

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Main Authors: Xenia Parisi, Anindita Ghosh, L. Jeffrey Medeiros
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:eJHaem
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Online Access:https://doi.org/10.1002/jha2.1074
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author Xenia Parisi
Anindita Ghosh
L. Jeffrey Medeiros
author_facet Xenia Parisi
Anindita Ghosh
L. Jeffrey Medeiros
author_sort Xenia Parisi
collection DOAJ
description Abstract Introduction The RAM immunophenotype (IP) in acute myeloid leukemia (AML) is defined by blasts with bright CD56 and weak‐to‐negative CD45, HLA‐DR, and CD38 expression. A RAM IP predominantly presents in infants who have “standard‐risk disease” under current criteria but, when treated accordingly, have devastatingly high rates of minimal residual disease and relapse with lower 3‐year and overall survival rates. However, given the relative rarity of this phenotype, it is neither well‐defined nor readily diagnosed. Methods We reviewed the electronic medical records of our institution from 1990 to 2024 for cases of AML expressing bright CD56 on flow cytometry and identified three cases with a RAM IP. Further, we performed a thorough literature search and reviewed impactful studies on pediatric AML and case/series reports of patients with a RAM IP, leading to the identification of 38 more cases. Results A total of 41 patients were collected. These patients were toddler age (1–3 years) with an equal sex distribution and clinically presented with low circulating blasts and cytopenias. Blasts were typically French–American–British M0 or M7. Immunophenotypically, CD33 and CD117 showed positivity in >90% of cases, with CD19, CD34, CD41, and CD42b, frequently positive. Half of the cases were positive for CD7 and CD61. T‐cell/myeloid markers were rare, except for cytoplasmic CD3, seen in 1/3, apparently correlating with CBFAT2T3:GLIS1 fusions. Gains in chromosomes 21, 13, and 8 and CBFAT2T3::GLIS1 fusions were frequent. Conclusion AML with a RAM IP has a poor prognosis. This study offers a detailed characterization of the clinicopathologic patterns associated with this rare entity, which may help formulate the most appropriate diagnostic approach.
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spelling doaj-art-d04d3be5bc484b1fa451dc8e83419a3a2025-08-20T02:46:51ZengWileyeJHaem2688-61462025-02-0161n/an/a10.1002/jha2.1074Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature reviewXenia Parisi0Anindita Ghosh1L. Jeffrey Medeiros2Division of Pathology and Laboratory Medicine Department of Hematopathology The University of Texas MD Anderson Cancer Center Houston Texas USADivision of Pathology and Laboratory Medicine Department of Hematopathology The University of Texas MD Anderson Cancer Center Houston Texas USADivision of Pathology and Laboratory Medicine Department of Hematopathology The University of Texas MD Anderson Cancer Center Houston Texas USAAbstract Introduction The RAM immunophenotype (IP) in acute myeloid leukemia (AML) is defined by blasts with bright CD56 and weak‐to‐negative CD45, HLA‐DR, and CD38 expression. A RAM IP predominantly presents in infants who have “standard‐risk disease” under current criteria but, when treated accordingly, have devastatingly high rates of minimal residual disease and relapse with lower 3‐year and overall survival rates. However, given the relative rarity of this phenotype, it is neither well‐defined nor readily diagnosed. Methods We reviewed the electronic medical records of our institution from 1990 to 2024 for cases of AML expressing bright CD56 on flow cytometry and identified three cases with a RAM IP. Further, we performed a thorough literature search and reviewed impactful studies on pediatric AML and case/series reports of patients with a RAM IP, leading to the identification of 38 more cases. Results A total of 41 patients were collected. These patients were toddler age (1–3 years) with an equal sex distribution and clinically presented with low circulating blasts and cytopenias. Blasts were typically French–American–British M0 or M7. Immunophenotypically, CD33 and CD117 showed positivity in >90% of cases, with CD19, CD34, CD41, and CD42b, frequently positive. Half of the cases were positive for CD7 and CD61. T‐cell/myeloid markers were rare, except for cytoplasmic CD3, seen in 1/3, apparently correlating with CBFAT2T3:GLIS1 fusions. Gains in chromosomes 21, 13, and 8 and CBFAT2T3::GLIS1 fusions were frequent. Conclusion AML with a RAM IP has a poor prognosis. This study offers a detailed characterization of the clinicopathologic patterns associated with this rare entity, which may help formulate the most appropriate diagnostic approach.https://doi.org/10.1002/jha2.1074acute megakaryocytic leukemiaacute myeloid leukemiaCBFAT2T3::GLIS2pediatric leukemiaRAM phenotype
spellingShingle Xenia Parisi
Anindita Ghosh
L. Jeffrey Medeiros
Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
eJHaem
acute megakaryocytic leukemia
acute myeloid leukemia
CBFAT2T3::GLIS2
pediatric leukemia
RAM phenotype
title Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
title_full Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
title_fullStr Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
title_full_unstemmed Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
title_short Acute myeloid leukemia with RAM immunophenotype: A report of three patients and comprehensive literature review
title_sort acute myeloid leukemia with ram immunophenotype a report of three patients and comprehensive literature review
topic acute megakaryocytic leukemia
acute myeloid leukemia
CBFAT2T3::GLIS2
pediatric leukemia
RAM phenotype
url https://doi.org/10.1002/jha2.1074
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