Rare diseases · Sign or symptom
Type IV atherosclerotic lesion
HP:0002635
What it means
In type IV atherosclerotic lesions a dense accumulation of extracellular lipid occupies an extensive but well-defined region of the intima. This type of extracellular lipid accumulation is known as the lipid core. A fibrous tissue increase is not a feature, and complications such as defects of the lesion surface and thrombosis are not present. The type IV lesion is also known as atheroma. Type IV is the first lesion considered advanced in this classification because of the severe intimal disorganization caused by the lipid core. The characteristic core appears to develop from an increase and the consequent confluence of the small isolated pools of extracellular lipid that characterize type III lesions. The increase in lipid is believed to result from continued insudation from the plasma. Type IV lesions, when they first appear in younger people, are found in the same locations as adaptive intimal thickenings of the eccentric type. Thus, atheroma is, at least initially, an eccentric lesion.
Rare diseases that can present with this1
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Atheromatosis
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.