Fact-sheet: Adventitial cystic disease
- Arterial subadventitial cyst
Updated on 12/05/2024 at 5:04 PM
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Definition
Rare cause of vascular disease due to compression.
Poorly understood entity, several pathophysiological hypotheses:
- Common embryologic mesenchymal origin of the arteries and joint synovium and their parallel development (embryonic synovial remnants sequestered in the arterial adventitia, or migration of synovial cells to the adventitia of the popliteal artery from an articular artery).
- Mucoid cystic degeneration of an arterial dissection located between the adventitia and the media.
- Synovial metaplasia of the adventitia induced by repeated trauma.
Oblong cystic formation developing within the arterial wall (gelatinous content), more or less connected to a joint cavity by a fistulous tract.
Most commonly: involvement of the popliteal artery, located on the anterior aspect of the artery, unilateral, length between 1 and 8 cm, diameter of 1.5-2 cm.
Less typical features possible: multifocal lesions, circumferential involvement of the arterial wall.
Various other locations possible (even rarer): iliac arteries and upper limb arteries, veins...
Clinical features
Young adult (mean age 43 years, 70% of diagnoses between 25 and 55 years), male predominance (sex ratio 15M/1F).
The artery often remains patent and thromboses late (slow evolution of the cyst).
Symptomatology related to the degree of arterial compression exerted by the adventitial cyst on the affected artery.
Typical case: unilateral calf intermittent claudication, progressively worsening in a young man, persisting after exertion, with no particular history and non-smoker (the overall picture differing from the classic presentation of atherosclerotic claudication).
Pulses palpable (except in the case of late complication with arterial thrombosis).
Ultrasound
Iso- or hypoechoic intramural formation (single or multiple), without posterior enhancement (unlike an arterial dissection or aneurysm).
To characterize: degree of stenosis, shape and dimensions of the cyst.
CT
Well-defined hypodense intramural formation (fluid density), not enhancing after injection.
Example below of a popliteal adventitial cyst on contrast-enhanced CT (cyst in red):
MRI
Oblong fluid-filled cystic formation (T2 hyperintense, T1 hypointense), without enhancement after gadolinium injection.
Example below of a popliteal adventitial cyst (arterial lumen in yellow, cyst in red) on sagittal images:
Vascular intervention
Three angiographic appearances have been described (nonspecific):
- "Hourglass" appearance of the popliteal artery, corresponding to progressive, centered compression of the arterial lumen.
- Lateral "scimitar" or "watch-glass" indentation on the artery, corresponding to lateral compression.
- Arterial thrombosis with a "flute-beak" cutoff.
Below: "scimitar" appearance related to the lateral indentation of the cyst on the popliteal artery (red).
Management
The natural course of the cyst is most often progressive volume increase, resulting in worsening popliteal compression.
Risks: thrombotic complication with acute severe ischemia in young patients.
Surgical treatment is most often used (endovascular treatment with angioplasty +/- stenting may be considered in older patients).