Acute eosinophilic leukemia (AEL) is a rare subtype of
acute myeloid leukemia
Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cell production. Symptoms may inclu ...
with 50 to 80 percent of
eosinophilic
Eosinophilic (Greek suffix -phil-, meaning ''loves eosin'') is the staining of tissues, cells, or organelles after they have been washed with eosin, a dye.
Eosin is an acidic dye for staining cell cytoplasm, collagen, and muscle fibers. ''E ...
cells in the blood and marrow. It can arise
de novo or may develop in patients having the chronic form of a
hypereosinophilic syndrome
Hypereosinophilic syndrome is a disease characterized by a persistently elevated eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any recognizable cause, with involvement of either the heart, nervous sys ...
. Patients with acute eosinophilic leukemia have a propensity for developing
bronchospasm
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes di ...
as well as symptoms of the
acute coronary syndrome
Acute coronary syndrome (ACS) is a syndrome (a set of signs and symptoms) due to decreased blood flow in the coronary arteries such that part of the heart muscle is unable to function properly or dies. The most common symptom is centrally l ...
and/or
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
due to
eosinophilic myocarditis and eosinophil-based
endomyocardial fibrosis
Hypereosinophilic syndrome is a disease characterized by a persistently elevated eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any recognizable cause, with involvement of either the heart, nervous sys ...
.
Hepatomegaly
Hepatomegaly is the condition of having an enlarged liver. It is a non-specific medical sign having many causes, which can broadly be broken down into infection, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdo ...
and
splenomegaly
Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of ''hypersplenism'' which include: some reduction in number of circulatin ...
are more common than in other variants of AML.
Diagnosis
A specific histochemical reaction, cyanide-resistant peroxidase, permits identification of leukemic blast cells with eosinophilic differentiation and diagnosis of acute eosinoblastic leukemia in some cases of AML with few identifiable eosinophils in blood or marrow.
Treatment and prognosis
when there is eosinophilia with increased immature precursors along with blasts; one need to identify lineage of blasts. As per old FAB classification most of the time blast lineage will be myeloid and may fall in M4EO of FAB classification. This entity need treatment like acute myeloid leukemia. However more rarely Eosinophilic leukemia may have underlying lymphoid blasts with t(5;14) (IL3;IGH).
with this gene fusion and eosinophilic cytokine comes under control of immunoglobulin heavy chain (IgH) locus. This entity need treatment as ALL. Overall prognosis is not dependent on eosinophilia but underlying lineage and genetic abnormalities.
References
External links
{{Myeloid malignancy
Acute myeloid leukemia