Fibrodysplastic Popliteal Aneurysm and Dilatation of Pedal Artery
Article Outline
We report a case of an asymptomatic popliteal aneurysm due to fibromuscular dysplasia (FMD), associated with suspected FMD of pedal artery on a 63-year-old woman. The popliteal aneurysm was resected. An in situ interposition of a short segment of hypogastric artery was performed to restore the arterial continuity. Popliteal FMD was confirmed by histological findings. Only 5 cases are reported in literature. FMD of pedal artery was suspected on the CT-scan aspect. FMD is a rare cause of popliteal aneurysm. To our knowledge, this is the first report of suspected fibrodysplastic dilatation of a foot artery.
Introduction
Fibromuscular dysplasia (FMD) is a rare cause of popliteal aneurysm. Only 5 cases are reported in the literature.1, 2, 3, 4 We report a case of popliteal aneurysm due to FMD, associated with dilatation of pedal artery, suspected to be due to FMD. To our knowledge, this is the first report of dilatation of suspected fibrodysplastic dilatation of a foot artery.
Case Report
A 63-year-old woman was referred to our unit for an asymptomatic right popliteal aneurysm. It was discovered on MRI done for a meniscus disorder. Her medical history included an oophorectomy and hysterectomy for benign pathology in 1998 and breast cancer treated by surgery and radio-chemotherapy in 2000. She had no vascular risk factors. Physical examination showed that all peripheral pulses were present, with a right ABI of 1. Duplex ultrasound showed a 16-mm right popliteal aneurysm without thrombus, with good runoff vessels. Angio CT-scan (Fig. 1A) showed an 18-mm right saccular popliteal aneurysm, at the level of intercondylar notch of femur. There was no sign of popliteal entrapment. Right pedal artery (Fig. 1B) was irregular with beading and corrugated aspect, without thrombus. There was no controlateral arterial anomaly. There was no anomaly on carotid and renal arteries. Serologies (HIV, HCV, HBV and syphilis) were negative. As peripheral veins were not usable on duplex ultrasound, decision to use hypogastric artery as a conduit was taken. Angio-MRI showed two patent hypogastric arteries, without anomaly. Harvesting of right hypogastric artery was done first. Then the patient underwent resection of popliteal aneurysm, through a posterior approach. An in situ interposition of a short segment of hypogastric artery was performed. Postoperative course was uneventful.
Fig. 1
1A: 3D contrast-enhanced CT reconstructions showing right saccular popliteal aneurysm, localized behind the right intercondylar notch of femur. 1B: 3D contrast-enhanced CT reconstructions showing dilatation of the right pedal artery (black arrow) with corrugated aspect.
Histological examination (Figs. 2A, 2B) showed medial thickening and disorganization, with irregular intimal collagenous fibrosis. Collagenous fibrosis interrupted and duplicated the internal elastic membrane. There was no evidence of inflammatory disease no sign of atherosclerosis. These histopathologic features were typical of fibromuscular dysplasia of peri-medial type.
Fig. 2
histological pictures of the right resected popliteal aneurysm. 2A: the lumen of the artery is dilated (aneurysm) and irregular due to irregular thickness wall (HPS). 2B: original magnification (Orceine, X 20) showing overall disorganization of the wall. There is an intimal proliferation that reaches the media. Focally disrupture (∗) and reduplication of internal elastic membrane (∗∗) is also seen, with medial disorganization.
At one year follow-up, patient was asymptomatic. The graft was patent, without anastomotic anomaly.
Discussion
Contrary to atherosclerosis, FMD is a rare cause of popliteal aneurysm. In young woman, first etiology of such an aneurysm is popliteal entrapment and popliteal FMD. Atherosclerotic popliteal aneurysm is known to be a very rare condition in woman.5 Infection, trauma or Takayasu disease are secondarily discussed.4 We found 4 publications1, 2, 3, 4 in literature, with 5 reported cases, of FMD popliteal aneurysm with histological proofs. We also found a case report6 of popliteal aneurysm assigned to FMD, while histological examination had shown a non-specific sclerosis. FMD is also known to be responsible for popliteal stenosis, with beading aspect, or occlusion.1, 7, 8, 9, 10 A literature review1, 2, 3, 4 (Table 1) showed a small predominance for female cases (3 females / 2 men). In literature,1, 2, 3, 4 patients were younger (from 10 to 39 years) than ours. Two popliteal aneurysms were symptomatic, in the two youngest patients.1, 2 Bilateral popliteal aneurysms were observed in the youngest patient.2 The diameter of asymptomatic popliteal aneurysms was small,2, 3, 4 between 12 and 18
mm, including our case. We decided to operate on our asymptomatic patient taking into account risks of complication of such lesion (rupture, thrombosis, embolism).1, 2, 4 It is interesting to underline that localization of popliteal aneurysm is exactly the same in three cases, including our case,3, 4 at the level of intercondylar notch of femur. Exact localization of the other cases was not strictly reported, two of them had occluded popliteal aneurysm.1, 2
Table I. Characteristics of popliteal aneurysm due to FMD, with histologic proof (literature review and current case)
| Study | No. of cases | Age (yr) | Sex | Symptomatology | Characteristics of aneurysm (form, diameter, localization) | Treatment | Histologic conclusion |
|---|---|---|---|---|---|---|---|
| Price and Vawter1 | 1 | 16 | M | Intermittent claudication of right lower limb | Right occluded popliteal aneurysm | Popliteal resection | Fibromuscular dysplasia |
| Stinnett et al.2 | 2 | 10 | F | Left subacute lower limb ischemia | Left occluded popliteal aneurysm | Distal thrombectomy and femoropopliteal bypass (reversed segment of great saphenous vein) | NA |
| Asymptomatic on the right lower limb | Right, saccular, 12 mm | Popliteal resection, femoropopliteal bypass (reversed segment of great saphenous vein) | Medial fibrodysplasia | ||||
| Fiche et al.3 | 1 | 20 | M | Asymptomatic | Right, fusiform, 15 mm at the level of intercondylar notch of femur | Popliteal resection, popliteopopliteal bypass (reversed segment of great saphenous vein) | Medial fibrodysplasia |
| Neukirch et al.4 | 1 | 39 | F | Asymptomatic | Left, saccular, 13 mm at the level of intercondylar notch of femur | Popliteal resection, direct end-to-end anastomosis | Medial fibrodysplasia |
| Current case | 1 | 63 | F | Asymptomatic | Right, saccular, 18 mm at the level of intercondylar notch of femur | Popliteal resection, in situ interposition of a short segment of hypogastric artery | Perimedial fibrodysplasia |
| Irregular and corrugated pedal artery (CT scan) |
We performed a popliteal resection as in three cases of literature1, 2, 3, 4 (Table 1). In literature, saphenous vein was used to restore the popliteal continuity in three cases.2, 3 Isolated popliteal resection was reported by Price.1 Direct end-to-end anastomosis was described by Neukirch.4 In our case we decided to use hypogastric artery as arterial graft, since peripheral veins were not usable and because we did not want to use a prosthetic bypass. Hypogastric artery is commonly used to restore renal patency for example,11 even if FMD can not always be excluded.12 In renal localization, patency rates of such autogenous grafts are good, with less late complications, compared to the saphenous grafts.11
In our case, FMD was confirmed by histological examination for popliteal aneurysm. For pedal artery, FMD was only suspected in this context because of its CT-scan aspect. To our knowledge this is the first report of such a dilatation of foot artery, probably due to FMD. Iwai8 and Patra9 described angiographic FMD of leg arteries (string of bead appearance,8 occlusion of leg arteries,9) without description of lesion on foot arteries. We can imagine that the good resolution of current exams, like 64-channel thin slices CT-scan, will likely allow diagnosing FMD lesion of peripheral arteries.
Etiologies of FMD are still debated. Different causes have been postulated (hormonal influence, physical stretching of the artery, mural ischemia by compromised vasa vasorum or popliteal entrapment).10 As we have seen before, popliteal aneurysm is often localized behind the intercondylar notch of femur, which is more in favour of a local cause (mechanical cause, local mural ischemia).
FMD most often affects renal arteries resulting in renovascular hypertension.13 Carotid involvement represents the second preferential localization of FMD.13 In literature review, as in our case, no other associated localization to fibrodysplastic popliteal aneurysm was found. However, given the possible spread of lesions and the time latency, we agree with Neukirch4 concerning vascular explorations of supra-aortic and renal arteries, which are recommended during the follow-up.
In conclusion, FMD is a rare cause of popliteal aneurysm and should be especially suspected in a young female. Histologic proof is mandatory in order to assert the FMD aetiology. Better resolution of current vascular explorations, as CT-scan, should allow the diagnosis of peripheral associated dilatation, as in our case.
References
- . Arterial fibromuscular dysplasia in infancy and childhood. Arch Pathol. 1972;93:419–426
- . Fibromuscular dysplasia and thrombosed aneurysm of the popliteal artery in a child. J Vasc Surg. 1987;5:769–772
- . Medial fibrodysplasia and aneurysm of the popliteal artery. Ann Vasc Surg. 1991;5:456–458
- Popliteal aneurysm due to fibromuscular dysplasia. Ann Vasc Surg. 1996;10:578–581
- Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard?. J Vasc Surg. 2007;45:706–715
- Popliteal aneurysm due to fibromuscular dysplasia. J Mal Vasc. 1986;11:9–12
- Fibrodysplasia of the popliteal arteries. Angiology. 1982;33:1–5
- Fibromuscular dysplasia in the extremities. J Cardiovasc Surg. 1985;26:496–501
- Fibromuscular dysplasia of leg arteries. A case report. J Mal Vasc. 1987;12:185–188
- . Femoropopliteal arterial fibrodysplasia. Br J Surg. 1990;77:396–399
- Long-term results of renal artery reconstruction with autogenous artery in patients with renovascular hypertension. Eur J Vasc Endovasc Surg. 1989;3:515–521
- Aortorenal arterial autografts: long-term assessment. Arch Surg. 1981;116:1416–1422
- Arterial fibrodysplasia. Histopathologic character and current etiologic concepts. Arch Surg. 1975;110:561–566
PII: S0890-5096(09)00169-1
doi:10.1016/j.avsg.2009.07.004
© 2009 Annals of Vascular Surgery Inc. Published by Elsevier Inc All rights reserved.
