Fibromuscular dysplasia classification: Difference between revisions
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=== Histological classification === | === Histological classification === | ||
In this classification system, FMD categorized according to the arterial layer involved. | In this classification system, FMD categorized according to the arterial layer involved. | ||
*'''Medial | *'''Medial dysplasia''' | ||
** | **Medial dysplasia is the most common type of FMD, and accounting for more than 80 percent of fibromuscular lesions. Medial FMD is further subdivided into three subtypes: medial fibroplasia, perimedial fibroplasia, and medial hyperplasia. | ||
. medial fibroplasia Microscopically is accompanying with alternating areas of thinned and thickened media. thickened area are fibromuscular ridges containing collagen as well thinned areas due to smooth muscle and internal elastic lamina loss with resultant arterial stenoses alternating with dilatation. | |||
This type is characterized by the classic "string of beads" appearance angiographically. | |||
Perimedial fibroplasia is associated with collagen deposition in the outer half of the media; and medial hyperplasia, in which there is true smooth muscle hyperplasia without significant fibrosis as well as collagen deposition | |||
* | <ref name="pmid1131001">{{cite journal |vauthors=Stanley JC, Gewertz BL, Bove EL, Sottiurai V, Fry WJ |title=Arterial fibrodysplasia. Histopathologic character and current etiologic concepts |journal=Arch Surg |volume=110 |issue=5 |pages=561–6 |date=May 1975 |pmid=1131001 |doi= |url=}}</ref> | ||
*'''Intimal fibroplasia''' (which accounts for approximately 10 percent of FMD) is caused by circumferential or eccentric deposition of collagen in the intima (image 2). The internal elastic lamina may be intact, fragmented, or duplicated, the latter especially in the childhood form. There is no inflammatory or lipid component. | |||
*'''Adventitial''' hyperplasia, also a rare manifestation, is caused by expansion of the fibrous adventitia; collagen extends into the periarterial fat, with accompanying inflammation | |||
The third major histological subtype, adventitial or periarterial | |||
disease, accounted for <1% of lesions. This is notable for | |||
collagen deposition surrounding the adventitia and extending into the periarterial tissue, with focal infiltration of lymphocytes | |||
being common. | |||
==References== | ==References== | ||
Revision as of 05:34, 22 June 2018
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Fibromuscular dysplasia Microchapters |
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Diagnosis |
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Treatment |
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ASA/ACCF/AHA Guideline Recommendations |
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Management of Patients With Fibromuscular Dysplasia of the Extracranial Carotid Arteries |
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Case Studies |
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Fibromuscular dysplasia classification On the Web |
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American Roentgen Ray Society Images of Fibromuscular dysplasia classification |
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Risk calculators and risk factors for Fibromuscular dysplasia classification |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohsen Basiri M.D.
Overview
- The classification system for fibromuscular dysplasia (FMD) was first according to the arterial layer involved. (intima, media , or adventitia) . However, with use of transluminal percutaneous angioplasty (TPA) for treatment of FMD lesions and its preference rather than surgery, the obtaining of pathological specimens are restricted. Thus, today, FMD is a disease diagnosed radiographically and histopathological classification has been replaced by the arteriographic findings.
Classification
Fibromuscular dysplasia may be classified according to angiographic findings or histological characteristics, as below:
Angiografic classification
- Multifocal FMD
- With angiographic appearance of a "string of beads" due to multiple areas of stenosis and dilatation(image; this subtype corresponds pathologically to medial fibroplasia.
- Focal FMD
- This form is less common (image 2), and it has the angiographic appearance of a "circumferential or tubular stenosis" and corresponds pathologically to intimal fibroplasia. Medial hyperplasia and periarterial hyperplasia are histologic types that may also have a focal appearance.
It has been shown that these two different angiographic subtypes of FMD (multifocal and focal) have different phenotypic presentations and natural history.[1]
Histological classification
In this classification system, FMD categorized according to the arterial layer involved.
- Medial dysplasia
- Medial dysplasia is the most common type of FMD, and accounting for more than 80 percent of fibromuscular lesions. Medial FMD is further subdivided into three subtypes: medial fibroplasia, perimedial fibroplasia, and medial hyperplasia.
. medial fibroplasia Microscopically is accompanying with alternating areas of thinned and thickened media. thickened area are fibromuscular ridges containing collagen as well thinned areas due to smooth muscle and internal elastic lamina loss with resultant arterial stenoses alternating with dilatation.
This type is characterized by the classic "string of beads" appearance angiographically.
Perimedial fibroplasia is associated with collagen deposition in the outer half of the media; and medial hyperplasia, in which there is true smooth muscle hyperplasia without significant fibrosis as well as collagen deposition
[2]
- Intimal fibroplasia (which accounts for approximately 10 percent of FMD) is caused by circumferential or eccentric deposition of collagen in the intima (image 2). The internal elastic lamina may be intact, fragmented, or duplicated, the latter especially in the childhood form. There is no inflammatory or lipid component.
- Adventitial hyperplasia, also a rare manifestation, is caused by expansion of the fibrous adventitia; collagen extends into the periarterial fat, with accompanying inflammation
The third major histological subtype, adventitial or periarterial disease, accounted for <1% of lesions. This is notable for collagen deposition surrounding the adventitia and extending into the periarterial tissue, with focal infiltration of lymphocytes being common.
References
- ↑ Sebastien Savard, Olivier Steichen, Arshid Azarine, Michel Azizi, Xavier Jeunemaitre & Pierre-Francois Plouin (2012). "Association between 2 angiographic subtypes of renal artery fibromuscular dysplasia and clinical characteristics". Circulation. 126 (25): 3062–3069. doi:10.1161/CIRCULATIONAHA.112.117499. PMID 23155180. Unknown parameter
|month=ignored (help) - ↑ Stanley JC, Gewertz BL, Bove EL, Sottiurai V, Fry WJ (May 1975). "Arterial fibrodysplasia. Histopathologic character and current etiologic concepts". Arch Surg. 110 (5): 561–6. PMID 1131001.