Chronic Myeloid Neoplasms
Myeloproliferative neoplasms (MPN)
Chronic eosinophilic leukemia (CEL) not otherwise categorized

Author: Nikhil Sangle, M.D. (see Authors page)

Revised: 3 March 2017, last major update August 2011

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Chronic eosinophilic leukemia CEL not otherwise categorized

Cite this page: Chronic eosinophilic leukemia (CEL) not otherwise categorized. website. Accessed December 16th, 2017.
Definition / general
  • "Not otherwise categorized" because there are no rearrangements of PDGFRA, PDGFRB or FGFR1 genes
  • Much rarer than reactive eosinophilia
  • Note: published cases without molecular analysis may be chronic eosinophilic leukemia, hypereosinophilic syndrome, myeloid neoplasms associated with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1 or mast cell disease (with eosinophilia)
  • Usually multiorgan disease (heart, lungs, CNS, GI tract, skin) due to eosinophil infiltration and release of cytokines and other substances from eosinophil granules
Diagrams / tables

Images hosted on other servers:

Nature images:

Diagnostic algorithm (WHO 2008)

  • Bone marrow examination with tryptase (to identify mast cells), T cell clonal studies, immunohistochemistry, cytogenetic studies and molecular studies to detect (and rule out) PDGFRA, PDGFRB or FGFR1 rearrangements

Diagnostic criteria:
  • ≥ 1.5 × 109/L peripheral blood eosinophils (persistent)
  • Either peripheral blood blasts > 2%, bone marrow blasts > 5% or abnormal cytogenetics; exclusion of secondary eosinophilia
  • Exclusion of other acute or chronic myeloid neoplasms
  • No evidence of phenotypically abnormal or clonal T lymphocytes
  • No evidence of PDFGRA, PDGFRB or FGFR1 rearrangements
  • Note: WHO 2001 included criterion of evidence of clonality (Blood 2004;104:3836), which is not explicitly indicated in WHO 2008
Case reports
Microscopic (histologic) description
  • Peripheral blood: mostly mature eosinophils, occasionally immature forms; no / occasionally mildly dysplastic forms
  • May have increased neutrophil count
  • Bone marrow: hypercellular marrow with marked increased in eosinophil precursors
  • Normal erythroid, neutrophil and megakaryocyte maturation
  • Normal or mildly increased myeloblasts
  • Variable dysplastic changes
Microscopic (histologic) images
All images from cases before molecular studies were indicated

Images hosted on PathOut server:

Bone marrow biopsy:

Markedly fibrotic marrow #1 (therapy was unsuccessful); #2 shows blasts and immature cells throughout fibrotic tissue

Markedly hypercellular due to
eosinophils and precursors,
megakaryocytes are markedly reduced,
reticulinfibers are increased

Electron microscopy images

Images hosted on PathOut server:

Abnormal eosinophil with decreased granules,
most granules are homogeneous
(normal eosinophilic granules have dense
core surrounded by less dense capsule)

Molecular / cytogenetics description
  • Usually no abnormalities
Differential diagnosis
  • Reactive eosinophilia due to parasitic infections, allergies, pulmonary diseases such as Löeffler syndrome, collagen vascular disorders; T cell lymphoma or Hodgkin lymphoma; acute or chronic myeloid neoplasms; mast cell disease