A rare type of acute leukemia in peripheral blood smear

Keywords
Erythroleukemia; Erythroblastic leukemia; Acute erythroblastic leukemia; Di Guglielmo's disease

A 80-years-old woman presented with 6-weeks history of fatigue and shortness of breath. Hemoglobin was 9.7 g/dL, platelets were 79 × 10³ /μL, leukocytes were 4.06 × 10³ /μL and B12 vitamin level was <200 pg/ml (reference value 197 - 771). After administration of cyanocobalamin her B12 vitamin level improved, but the anemia got progressively worse (hemoglobin was 3.7 g/dl) and reticulocyte count did not improve. A peripheral blood smear showed proerythroblasts (Figures 1, 2). Bone marrow aspirates and biopsy showed hypercellularity, being mainly erythroid progenitors, constituting >80% of bone marrow cell count with >30% proerythroblast without a significant myeloblastic component. The erythroid progenitors exhibited CD45+, CD34-, CD71+ and CD117+ by flow cytometry, and E-cadherin+, CD71+ and TP53+ by immunohistochemical staining. Fluorescence in situ hybridization analysis showed deletion 5q and loss of TP53. Karyotype showed deletion 5q, and derivates chromosomes 17 (included loss of TP53 gen) and 19. Next-generation sequencing panel detected potentially pathogenic variants in TET2 (VAF 28%) and TP53 (VAF 40%) genes. The findings were diagnostic of pure erythroblastic leukemia (PEL). Our patient was treated with azacytidine and blood transfusion support with a poor response over five months of follow-up.

Figure 1
Peripheral blood smear. Proerythroblasts; panel A-H: erythroid progenitors having large irregular nuclei, dispersed chromatin, some with prominent nucleoli, deeply basophilic cytoplasm, and high nuclear to cytoplasmic ratios. Wright stain; 100X objective, original magnification X1000.

Figure 2
Proerytroblast in peripheral blood smear. Wright stain; 100X objective, original magnification X1000.

PEL is a rare type of acute leukemia that represents less than 1% of all cases of acute myeloid leukemia (previously called M6, by the French-American-British cooperative group).¹,² PEL may be therapy-related, preceded by a myelodysplastic syndrome or develop de novo.² PEL is defined in the 2016 WHO classification system, as a neoplastic proliferation of erythroid progenitors constituting > 80% of bone marrow cellularity with ≥30% proerythroblasts without a significant myeloblastic component.³ Reactive erythroid hyperplasia is a well-known morphologic mimic of PEL in many diverse clinical situations due to erythroid hyperplasia as non-neoplastic (eg, megaloblastic anemia) and neoplastic entities. Although clinical presentation, laboratory, cytogenetic and molecular studies may ultimately resolve the differential diagnosis (eg, P53 mutation, complex karyotype).⁴ PEL have a clinically aggressive course associated with a poor prognosis.¹

• Data availability statement

  Data sharing not applicable to this article as no datasets were gener-ated or analysed during the current study.

References

• ¹
  Wang W., Wang S.A., Medeiros L.J., Khoury J.D. Pure erythroid leukemia. Am J Hematol. 2017Mar;92(3):292-296.
• ²
  Gajendra S., Yadav A.K., Chugh B., Sood N., Bhargava M. Clinicohematologic and cytogenetic profile in a rare case of pure erythroid leukemia. Ann Hematol. 2019Aug;98(8):2005-2007.
• ³
  Arber D.A., Orazi A., Hasserjian R., Thiele J., Borowitz M.J., Le Beau M.M., et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016May 19;127(20):2391-405.
• ⁴
  Reinig E.F., Greipp P.T., Chiu A., Howard M.T., Reichard K.K. De novo pure erythroid leukemia: refining the clinicopathologic and cytogenetic characteristics of a rare entity. Mod Pathol. 2018;31(5):705-717.

Data availability

Data sharing not applicable to this article as no datasets were gener-ated or analysed during the current study.

Publication Dates

• Publication in this collection
  07 July 2023
• Date of issue
  Apr-Jun 2023

History

• Received
  27 Oct 2021
• Accepted
  4 Jan 2022
• Published
  25 Jan 2022