Selected Arterial and Venous Diseases
Case 5 -
Adventitial Cystic Disease of the Popliteal Artery
Alan G. Rose
A 25-year-old man presented with symptoms of intermittent claudication of his left lower leg.
Arteriography revealed a smooth-walled narrowing of the popliteal artery. The affected segment of the
artery was resected and replaced by a graft.
His histology shows a classical example of adventitial cystic disease (ACD) of the popliteal artery.
The arterial lumen is compressed due to the presence of a unilocular cystic space within the adventitial
layer affecting at least 50% of the circumference of the artery. Portion of the cyst is lined by
flattened, mesothelial-like cells, but most of the cyst lining is composed of bare collagen. Scanty
foamy histiocytes are also noted, but the cyst contents have been lost. A Touton type giant cell was
present in one area. Fresh operative hemorrhage is noted alongside the artery. The arterial intima
shows focal thickening with fibrous interruption of the internal elastic lamina and a zone of fresh intra
intimal hemorrhage. The wall of the adventitial cyst is composed of denser, more hyalinized collagen
than the adjacent adventitia and the cyst appears to be collapsed, unlike its tense, expanded condition
prior to excision and surgical incision. Medial sclerosis and hyalinization is noted in areas in the
parent artery. One level shows obliquely sectioned intima with scanty mural organizing thrombus, that
occupies portion of the arterial lumen and accounted for the surgical resection and grafting.
Case 5 - Figure 1 - Cystic adventitial disease has produced the space seen in the upper portion of the picture. Portion of the original arterial lumen (with some mural thrombus) is seen below this.
Adventitial cystic disease is an idiopathic, cystic accumulation of mucinous material in the
adventitia of an artery, possibly related to trauma, ectopic ganglion cyst or "dysplasia." 
The condition is defined as "a dysplastic lesion of vascular wall, of unknown cause, characterized by the
formation of a mucoid cystic mass, with or without a true cellular lining, in or around the adventitia of
an otherwise normal blood vessel (artery or vein)". 
ACD occurs near a joint, 10 times more often in the wall of medium or small arteries (especially the
popliteal artery behind the knee joint) than comparable-sized veins. ACD accounts for one in 1200 cases
of limb claudication and is 5-8 times more frequent in men, usually manual laborers with a mean age of 40
years (range 10-70 years). The cyst may even envelop the entire circumference of the artery. About 250
cases of ACD have been reported in the literature up to the mid-1990s. On angiography, ACD gives an
appearance of a smooth-walled, fluted stenosis, or rarely it may produce total occlusion of the affected
artery, which may be displaced laterally or in an anteroposterior direction. Incomplete excision of the
"cyst" may lead to its recurrence. In addition to intra-arterial cysts, there may be additional mucinous
filled cysts within the adjacent popliteal fossa.
Microscopy characteristically shows an encapsulated cystic cavity filled with a gelatinous content
that has the staining properties of glycoprotein and acid mucopolysaccharide and may contain collagen
fragments with minimal or no inflammatory features around the vessel wall. The cystic structure may be
unilocular or multilocular and its inner surface is rarely lined with a flattened cell layer of uncertain
origin. The latter finding has led to suggestions that the condition may represent ectopic synovial
lining (derived from the neighboring joint or synovial sheath) displaced into the adventitia of the
popliteal artery. The lectin-binding pattern of adventitial cystic disease appears to be similar to the
reactivity pattern of normal synovium.  Rarely, the media may share in the mucinous
The gelatinous contents of the cyst may be readily evacuated without opening the arterial lumen, but
bypass of the lesion may be needed if there is luminal occlusion. Angioplasty is not applicable for the treatment of ACD.
Several authors have reviewed ACD of arteries
and Lie et al.  reported the
condition in the lesser saphenous vein. The differential diagnosis includes popliteal entrapment
syndromes, atherosclerosis with or without superimposed thrombosis, fibromuscular dysplasia and
vasculitis e.g., Buerger syndrome. In the popliteal entrapment syndrome, chronic trauma inflicted by
pressure on the arterial wall, leads to a distinctive abnormal development of longitudinal muscle bundles
in the arterial media.
- Virmani R, Burke A, Farb A. Atlas of Cardiovascular Pathology. Philadelphia, WB Saunders Company, 1996, p 186.
- Lie JT. Adventitial cystic disease (ACD). In Bloom S (ed), Lie JT, Silver MD (associate eds): Diagnostic criteria for cardiovascular pathology. Acquired diseases. Philadelphia, Lippincott-Raven 1997, pp. 151-152.
- Flanigan DP, Burnham SJ, Goodreau JJ, Bergan JJ. Summary of cases of adventitial cystic disease of the popliteal artery. Ann Surg 1979; 189: 165-175.
- Ishikawa K. Cystic adventitial disease of the popliteal artery and of other stem vessels in the extremities. Jap J Surg 1987; 17: 221-229.
- Lie JT, Jensen PL, Smith RE. Adventitial cystic disease of the lesser saphenous vein (Review). Arch Pathol Lab Med 1991; 115; 946-948.