Synonyms: Clonal hypereosinophilic syndrome | HES-M | HES-N | Neoplastic hypereosinophilic syndrome | Primary HES
A rare hypereosinophilic syndrome characterized by hypereosinophilia produced by clonal eosinophils derived from neoplastic stem cells in the absence of any secondary cause of eosinophilia and persisting for at least six months. The condition is associated with signs of organ infiltration dysfunction and damage. Clinical manifestations are highly variable depending on the organ systems involved and include dermatologic pulmonary cardiac gastrointestinal and cerebral manifestations among others.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
Newly diagnosed with
Primary hypereosinophilic syndrome?
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Advocacy Organizations
American Partnership For Eosinophilic Disease
APFED is dedicated to preventing and curing eosinophil-associated diseases while enhancing the quality of life for patients and families. We achieve this by passionately embracing, supporting, and advancing education, awareness, research, advocacy, and support initiatives for those affected.
Children’s Cardiomyopathy Foundation
CCF's mission is to accelerate the search for causes and cures for pediatric cardiomyopathy through increased research, education, awareness, advocacy, and support to affected children and their families.
Heart of a Giant Foundation
The mission of the HGF is to achieve better health outcomes for heart diseases and related chronic health conditions in our communities and enhance the quality of life through health education, care support, and connection to community resources.
HeartCharged
Ending preventable deaths from undiagnosed heart conditions and sudden cardiac arrest, especially in young people, and providing patient-to-patient support.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.