Surgical treatment of a primary external iliac vein aneurysm

Primary external iliac vein aneurysms are rare and can be complicated by thrombosis, pulmonary embolism, or rupture. To date, there are only 14 cases reported in the literature. In this paper we report a case of a 25-year-old man who presented with left lower limb edema and cyanosis. Vascular ultrasonography revealed a cystic tumor in the left iliac fossa. Computed tomography angiography confirmed that the finding was an external iliac vein aneurysm, measuring 3.8 cm at its largest diameter. The patient underwent surgical treatment with resection followed by longitudinal venorrhaphy, with no complications. After the procedure left limb symptoms improved. The patient has exhibited no late complications over 44 months of follow-up.


CASE REPORT
A 25-year-old, otherwise healthy male patient was admitted via emergency, presenting with spontaneous and insidious pain, swelling and a feeling of heaviness in the left lower limb.He had no history of traumas or of prior surgery.On clinical examination he exhibited edema and cyanosis of the entire left lower limb and the ipsilateral gluteal region.There were no palpable masses, murmurs or thrills anywhere in the abdominal area.Pulses in the lower limbs were symmetrical and normal.Laboratory tests found no abnormalities, but Doppler venous ultrasonography revealed a fusiform cystic mass with a maximum diameter of approximately 4.0 cm involving the left external iliac vein and with no sign of extrinsic compression.Venous angiotomography confirmed a diagnosis of a saccular venous aneurysm of the left external iliac vein with a maximum diameter of 3.8 cm and a small quantity of thrombi within the aneurysm sac (Figure 1).
The patient was given anticoagulant treatment with intravenous heparin until the time of surgery.Surgical access was obtained via a midline incision and the proximal and distal portions of the aneurysm were carefully identified and dissected, to avert the risk of embolization (Figure 2a).After systemic administration of intravenous heparin, the proximal and distal portions of the external iliac vein were clamped and longitudinal venotomy was conducted, followed by venous thrombectomy, resection of the excess vein wall and primary and continuous suture (longitudinal venorrhaphy) with Prolene 5.0 thread.After removal of the clamps, venous flow was reestablished (Figures 2c and 2c).There were no complications during surgery and no associated vascular intra-abdominal anomalies were observed.Histopathological examination of the resected venous segment did not detect any specific abnormalities.events during his stay in hospital and was discharged 5 days after surgery.At an outpatients follow-up visit, 30 days after hospital discharge, significant reduction of the edema was observed and the patients' initial complaints had completely resolved over 44 months of follow-up.

DISCUSSION
Aneurysms of the iliac vein are extremely rare.Ysa et al. 2 conducted a systematic review, identifying just 21 cases published in the literature, among which secondary aneurysms were most common, with ten cases related to arteriovenous fistulas caused by traumas, two patients with an associated cardiovascular anomaly, one patient with Iliac Vein Compression Syndrome, and another who developed the aneurysm after a heat injury to the iliac vein.At the time that that review was written, there were just seven published cases of primary aneurysms. 2e identified 14 cases of primary venous aneurysms involving the iliac vein described in the literature, in eight of which an external iliac vein was involved [1][2][3][4][5][6][7][8][9][10][11][12][13][14] (Table 1).Our patient, a young man, presented with pain and edema of the left lower limb as the most important complaints.A review of cases described in the literature shows that the majority (57%) were in male patients, aged from 19 to 69 years.The other published cases (43%) were in women aged 14 to 38.The majority of patients exhibited some type of symptom related to the venous aneurysm and five patients (38%) were asymptomatic.As with our patient, the most common clinical manifestations were pain and edema (57%) in the affected limb.
These symptoms could be related to increased venous pressure, as has been reported by other authors. 3In the great majority of cases (63%) only the left iliac vein was affected, while two patients (14%) only had right iliac vein involvement and another three patients (21.5%) had bilateral involvement.Although there was a small quantity of mural thrombi, our patient's venous aneurysm was not completely thrombosed, in common with some of the cases described. 1,4,6,7,10,11owever, in other situations, the aneurysm may be thrombosed at the time of diagnosis. 2,3,5,8,9Additionally, some authors have described patients with pulmonary thromboembolism secondary to an aneurysm of the iliac vein. 4,12,14ince there are so few cases described, treatment of this type of aneurysm has not yet been standardized.There are a range of possibilities, depending on the patient's clinical presentation, the size of the aneurysm, extent of venous thrombosis (when present) and presence of collateral circulation.Our patient was young and exhibited significant symptoms without complete thrombosis of the venous aneurysm.We therefore chose surgical treatment, with resection of the aneurysm by partial resection of the aneurysm wall followed by longitudinal venorrhaphy.The same technique was used by other authors with satisfactory results. 1,5,10,13In some situations other authors have chosen complete resection of the aneurysm and reconstruction of the vein with synthetic 3 or venous 7 grafts.Fully thrombosed aneurysms causing minor clinical manifestations and/or with abundant collateral venous networks can be treated clinically using anticoagulation. 2,9,12In cases in which extensive thrombosis involves the iliofemoral axis or cases in which the thrombosed segment involves the internal iliac vein, it is possible to proceed with ligature of the aneurysm only. 4,8linical follow-up of these patients is of fundamental importance, because venous reconstructions can develop thrombosis and patients may suffer relapse of symptoms. 3Our patient has been in follow-up for 44 months with total remission of the initial complaints of edema and pain in the left lower limb, and the most recent color Doppler venous ultrasonography did not detect thrombosis.Clinical follow up periods described in the literature vary from 3 to 36 months and the majority of these patients exhibited significant improvement of symptoms; but a certain proportion of residual edema may remain, primarily in cases in which thrombosis of the venous aneurysm had occurred. 2rom the perspective of pathology, the wall of the venous aneurysm may exhibit intimal fibrosis and thickening, and a reduction in the number of smooth muscle cells and thickening of the tunica media. 1,14ormal histopathological results have also been reported by other authors. 3n conclusion, this is a description of a rare case of primary aneurysm of the external iliac vein in which the patient exhibited symptoms of venous insufficiency in the left lower limb and was successfully treated with resection of the aneurysmal venous wall followed by longitudinal venorrhaphy, with no later complications.

Figure 2 .
Figure 2. Sequence of intraoperative photographs.a) Aneurysm of left external iliac vein with repair to proximal and distal portions.b) Venotomy and resection of excess venous wall.c) Appearance after longitudinal venorrhaphy.

Figure 1 .
Figure 1.Reconstruction of venous angiotomography showing voluminous aneurysm in left external iliac vein.

Table 1 .
Published cases of patients with primary aneurysms of the iliac vein.