Bone marrow neoplastic

Bone marrow - neoplastic myeloid


Hypereosinophilic syndrome

Topic Completed: 1 August 2011

Minor changes: 19 August 2021

Copyright: 2002-2019,, Inc.

PubMed Search: Hypereosinophilic syndrome [title] idiopathic

Nikhil Sangle, M.D.
Page views in 2020: 1,241
Page views in 2021 to date: 1,298
Cite this page: Sangle N. Hypereosinophilic syndrome. website. Accessed September 21st, 2021.
Definition / general
  • Diagnosis of exclusion; also called idiopathic hypereosinophilic syndrome
  • See also discussions in these chapters: Gallbladder-eosinophilic cholecystitis, Lung - nontumor: eosinophilic pneumonia
  • 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, T cell lymphoproliferative disorder or mast cell disease (with eosinophilia)
  • Bone marrow examination with tryptase (to detect mast cells), T cell clonality studies, immunohistochemistry, cytogenetic studies and molecular studies to detect (and rule out) PDGFRA, PDGFRB or FGFR1

Diagnostic criteria:
  • ≥ 1.5 × 109/L peripheral blood eosinophils (persisting for > 6 months), exclusion of secondary eosinophilia by appropriate thorough investigation(s), exclusion of other acute or chronic myeloid neoplasms, myelodysplastic syndrome and mast cell disorder, no evidence for phenotypically abnormal or clonal T lymphocytes, no cytogenetic abnormality, < 2% peripheral blasts and < 5% bone marrow blasts
  • Note: some studies add criterion of no evidence of clonality, which may be difficult to determine if no cytogenetic abnormalities are present - Diagnostic algorithm (WHO 2008)
Case reports of organ / tissue involvement
  • Immediate therapy may not be required if asymptomatic and no organ damage
  • Cytoreductive therapy includes corticosteroids, interferon alpha and hydroxyurea (Cancer J 2007;13:384)
Microscopic (histologic) description
  • Bone marrow: hypercellular marrow, increased eosinophilic precursors
Microscopic (histologic) images
Note: Images are from cases before molecular studies were indicated

Images hosted on PathOut server:

Peripheral blood:

Three eosinophils show marked hypogranulation
in 50 year old man with 3 year history of
hypereosinophilic syndrome with progressive
marrow failure and multiple organ involvement

Reactive eosinophilia (for comparison) shows normal
number and size of granules, occasional
vacuoles, and slightly hyperlobulated nuclei
(eosinophilia had no identifiable cause, gradually resolved)

Bone marrow smear:

50 year old patient (above) has marked increase
in eosinophils at all levels of maturation,
some granules are basophilic and some
eosinophilic myelocytes have reduced granules

Additional references
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