Cryptic PML-RARα positive acute promyelocytic leukemia with unusual morphology and cytogenetics

Indian J Pathol Microbiol. 2010 Oct-Dec;53(4):817-9. doi: 10.4103/0377-4929.72097.

Abstract

Acute Promyelocytic Leukemia (APL) is different from other forms of acute myeloid leukemia (AML), to the reason being the potential devastating coagulopathy and the sensitivity to all-trans retinoic acid (ATRA) and arsenic trioxide (As 2 O 3 ). We hereby present a case of APL, morphologically distinct from the hypergranular APL; however, the flow cytometry revealed a characteristic phenotype showing dim CD45, bright CD13, bright CD33 and dim CD117 positivity. These were negative for CD34, HLA-DR, B-lymphoid and T-lymphoid lineage markers. Conventional cytogenetics revealed a distinct karyotype of a male with translocation t(4;15)(q34.2:q26.3). However, interphase fluorescence-in-situ hybridization (FISH) revealed PML/RARA fusion signal on chromosome 15 in 90% cells. The cryptic translocations may be missed on conventional cytogenetics, however, need to be picked by other techniques as FISH.

Publication types

  • Case Reports

MeSH terms

  • Antigens, CD / analysis
  • Cell Nucleus / genetics
  • Flow Cytometry
  • Gene Fusion
  • HLA Antigens / analysis
  • Humans
  • In Situ Hybridization, Fluorescence
  • Karyotyping
  • Leukemia, Promyelocytic, Acute / diagnosis*
  • Leukemia, Promyelocytic, Acute / pathology*
  • Leukocytes / cytology*
  • Male
  • Middle Aged
  • Nuclear Proteins / genetics
  • Promyelocytic Leukemia Protein
  • Receptors, Retinoic Acid / genetics
  • Retinoic Acid Receptor alpha
  • Transcription Factors / genetics
  • Translocation, Genetic
  • Tumor Suppressor Proteins / genetics

Substances

  • Antigens, CD
  • HLA Antigens
  • Nuclear Proteins
  • Promyelocytic Leukemia Protein
  • RARA protein, human
  • Receptors, Retinoic Acid
  • Retinoic Acid Receptor alpha
  • Transcription Factors
  • Tumor Suppressor Proteins
  • PML protein, human