Chronic Eosinophilic Leukemia, NOS Flashcards
What is the definition of
chronic eosinophilic leukemia ?
- autonomous clonal proliferation of eosinophil precursors
- persistently increased eosinophils in the PB, BM, and peripehral tissues
- eosinophilia is the dominant abnormality
- organ damage
- from leukemic infiltration
- release of cytokines
- enzymes and other proteins
What is necessary for the diagnosis
of CEL, NOS ?
- eosinophil count of 1.5 x10^9/L in the blood
- <20% blasts in the peripheral blood and bone marrow
- evidence of clonality in the myeloid cells or an increase in peripheral blood/bone marrow blasts
In cases where there is no clear
evidence of clonality or increased blasts
what diagnosis is rendered ?
- Idiopathic Hypereosinophilic Syndrome
- eosinophilia ( >1.5 x10^9/L) persisting for > 6 months
- No underlying cause for the eosinophilia has been discovered
- presence of associated signs and symptoms of organ involvement and dysfunction
- no evidence of clonality
- may be caused by unrecognized release of eosinophil cytokines:
- IL2, IL3, and IL5
When can the diagnosis of
Idiopathic Hypereosinophilia be rendered ?
- when the criteria for idiopathic hypereosinophilic syndrome are met with the exception:
- NO evidence of tissue damage
What is the epidemiology of
CEL, NOS ?
- true incidence of these rare diseases is unknown
- seems to be more common in men
- generally in 7th decade
What is the localization of
CEL, NOS ?
- multisystem disease
- PB and BM
- tissue infiltration with damage by eosinophils
- heart, lung, CNS
- skin, GI tract
- spleen and liver
What are the clinical features
of CEL, NOS ?
- eosinophilia is sometimes incidentally identified
- constitutional symptoms:
- most severe: endomyocardial fibrosis with CHF
- weight loss, night sweats, fever, fatigue, cough
- pruritis, diarrhea
- angio-edema
- symptoms to organ specific infiltration are frequently seen
- rheumatologic manifestations are common
What is the most common finding
in the peripheral blood ?
- mature eosinophils are predominant
- few immature myelocytes and promeylocyte eosinophils
- range of eosinophil abnormalities (can be seen in reactive conditions as well)
- sparse granulation (clear cytoplasm)
- cytoplasmic vacuolization
- nuclear hypersegmentation or hyposegmentation
- increased size
If present, what morphologic finding
supports the diagnosis of CEL, NOS ?
- the presence of dysplasia in cells of other myeloid lineages
- generally have a neutrophilia with mild monocytosis
- diagnostic criteria for CMML are NOT met
- mild basophilia can be present
- blasts can be seen but should be <20%
What are the morphologic
findings in the bone marrow of CEL, NOS ?
- hypercellular due to eosinophil infiltration
- eosinophil maturation is orderly
- charcot leyden crystals are seen
- erythroids and megas are normal
- increased blasts (>2% PB, 5-19% BM) support the diagnosis as long as there are no dysplastic features in other cells lines
- marrow fibrosis is in 1/3 of cases but severe fibrosis is rare
What is the differential diagnosis/
entities that must be excluded in order to
diagnose CEL, NOS ?
- myeloid neoplasms with PDGFRA, PDGFRB or FGFR1 or PCM-JAK2
- ETV6-JAK2
- BCR-JAK2 fusion
- reactive eosinophilia
- parasitic infection, allergies, pulmonary diseases like Loffler syndrome, cyclical eosinophilia, angiolymphoid hyperplasia, collagen vascular disorders and Kimura disease
What neoplastic disorders can present
with eosinophilia ?
- T cell lymphomas
- Hodgkin Lymphoma
- Systemic mastocytosis
- Lymphoblastic leukemia
- AML
- MPNS
release of eosinophil stimulating cytokines leads to eosinophilia:
- IL2, IL3, IL5 or G-CSF
When there is eosinophilia and the
presence of increased spindle shaped mast cells
what genetic abnormality should be considered ?
- rearrangement of PDGFRA or PDGFRB
When can the diagnosis of
Lymphocytic variant of Hypereosinophilic Syndrome
be used?
- when a neoplastic T cell population is driving the eosinophilia and organ damage
- If the monocyte count is high, a diagnosis of CMML with eosinophilia may be more appropriate
When should the consideration of a
diagnosis of atypical CML with
eosinophilia be made ?
- BCR-ABL1 negative
- eosinophilia
- >10% neutrophil precursors in the peripheral blood
- no monocytosis
