Pure erythroid leukemia: a reassessment of the entity using the 2008 World Health Organization classification

Abstract

Pure erythroid leukemia (PEL) is rare, characterized by a neoplastic proliferation of erythroblasts. Given recent incorporation of molecular genetic findings and clinical features in the revised 2008 World Health Organization classification scheme of acute myeloid leukemia, we questioned if PEL still remains as a distinct subtype of acute myeloid leukemia. In this retrospective study, we identified 18 cases of acute leukemia with morphologic and immunophenotypic features of PEL. Following the current World Health Organization classification algorithm, these cases were classified as: 13 acute myeloid leukemia with myelodysplasia-related changes, 3 therapy-related acute myeloid leukemia, and 1 chronic myelogenous leukemia blast crisis, and one unclassifiable due to insufficient clinical information. All 16 cases with cytogenetic data harbored an extremely complex karyotype and the median overall survival of the 18 patients was 3 months (range, 1-7 months). This survival was significantly shorter than that of patients with acute erythroid leukemia, erythroid/myeloid subtype, or acute myeloid leukemia with myelodysplasia-related changes with erythroid predominance (Po0.001). PEL is characterized as a neoplastic erythroid hyperproliferation with maturation arrest. E-cadherin emerged as the most sensitive and specific marker for immature erythroblasts, and was helpful in distinguishing PEL from other erythroid proliferations. Our study showed that the criteria for acute myeloid leukemia in the 2008 World Health Organization system facilitate reclassification of PEL cases into other acute myeloid leukemia categories, mainly of acute myeloid leukemia with myelodysplasia-related changes. These new assigned categories fail to capture the distinct features of PEL, where the phenotype of PEL correlates with a very complex karyotype and an extremely aggressive clinical course.

Positive p53 immunostaining and erythroid maturation in two cases of pure erythroid leukemia with extremely complex karyotypes

“…Cytogenetically, no specific chromosome abnormality has been described in PEL, but complex karyotypes with multiple structural abnormalities are common, especially with -5/del(5q), -7/del(7q), and trisomy 8 [2,4]. Chromosomal abnormalities have been found in approximately 55% of adult AML cases.…”

“…This change was based on the close biologic relationship of the AEL-erythroid/myeloid type to MDS in terms of its clinical presentation, morphologic features, and genetic abnormalities [1]. PEL is very rare form of leukemia, and some cases of PEL occur as a disease progression stage that has evolved from MDS [2][3][4]. Morphologic, immunophenotypic, cytogenetic, and molecular analysis are valuable for confirming the diagnosis of PEL.…”

“…PEL is a rare leukemia, comprising less than 1% of all AML cases [2][3][4]. Approximately 39% of PEL cases evolved from myelodysplastic syndrome (MDS) [2]. Here, we describe two cases of PEL that evolved from MDS, noting the important clinical implications of their immunophenotypic, cytogenetic, and molecular features.…”

“…PEL is defined as a neoplastic proliferation of immature cells that have an undifferentiated or proerythroblastic appearance representing >80% immature erythroid precursors with >30% proerythroblasts in the bone marrow (BM) nucleated cells [1]. PEL is a rare leukemia, comprising less than 1% of all AML cases [2][3][4]. Approximately 39% of PEL cases evolved from myelodysplastic syndrome (MDS) [2].…”

Pure erythroid leukemia evolving from a therapy‐related myelodysplastic syndrome secondary to treatment for chronic lymphocytic leukemia

“…After rapid clinical deterioration, his goals of care were limited to palliation, and he expired 2 days later. PEL is a rare type of acute myeloid leukemia, which often arises from preceding myelodysplastic syndromes and may be therapy related in some cases [1][2][3][4]. Here, we present a highly unique and, to our knowledge, the first reported case of a PEL evolving out of a myeloid-neoplasm thought to be secondary to treatment for CLL.…”