Right Subclavian Vein Pseudoaneurysm Following Percutaneous Axillary Lymph Node Biopsy: A Case Report

Abstract

Subclavian vein pseudoaneurysms are rare vascular lesions, and only a few cases have been reported in the literature, with most attributed to blunt trauma. We describe the first reported case of a subclavian vein pseudoaneurysm following percutaneous axillary lymph node biopsy. A 42-year-old woman presented with a progressively enlarging, painless right neck mass 18 months after treatment for node-positive breast cancer. Imaging with duplex ultrasound and contrast-enhanced computed tomography demonstrated a large saccular pseudoaneurysm arising from the right subclavian vein without arterial communication. Following initial observation, open surgical repair was performed via a supraclavicular approach, with excision of the pseudoaneurysm and primary repair of the vein. The patient recovered without complications and remained asymptomatic at follow-up. This case adds to the limited literature on venous pseudoaneurysms, highlights a novel iatrogenic mechanism, and supports open aneurysmorrhaphy as a safe and effective treatment option in appropriately selected patients.

Introduction

Extremity venous pseudoaneurysms are rare vascular lesions and are most commonly reported in the lower extremities. ¹ Etiology of these pseudoaneurysms commonly include trauma (iatrogenic or otherwise), infection, and idiopathic.^2,3 Pseudoaneurysms of the subclavian vein are exceedingly rare, with limited reports in the literature, and are typically related to trauma. This report presents the case of a subclavian vein pseudoaneurysm following axillary lymph node biopsy, a mechanism not previously described.

Case Report

A 42-year-old woman presented with an enlarging, painless right neck mass that had become more prominent in the recent months. Her history was notable for right-sided node-positive breast cancer diagnosed 18 months prior. She had undergone core biopsy of the breast mass and axillary lymph nodes. A left-sided chemotherapy port was also placed via the subclavian vein, and there was no history of subclavian vein access or cannulation on the right side.

On examination, there was a soft, nonpulsatile mobile mass at the base of the right neck that enlarged with a Valsalva maneuver. There were no skin changes overlying the mass. The right upper limb had normal power and sensation across dermatomes C5-T1, and brachial and radial pulses were palpable and equal to the contralateral side.

Ultrasound of the mass demonstrated a 74 × 15 × 43 mm saccular outpouching arising from an 8 mm defect in the subclavian vein with venous flow on color doppler. The aneurysm did not communicate with any the adjacent arterial structures. Venous phase contrast-enhanced computed tomography (CT) scan demonstrated a large, homogenously enhancing mass arising from the right subclavian vein consistent with a venous pseudoaneurysm (Figures 1 and 2).

Figure 1.

Contrast enhanced venogram demonstrating a 50 mm outpouching from the subclavian vein in the coronal plane.

Figure 2.

Contrast-enhanced venogram demonstrating a 58 mm outpouching from the right subclavian vein with a 7 mm neck diameter in the sagittal plane. This pseudoaneurysm is distinct and separate to the right subclavian artery, and there is no evidence of an iatrogenic arteriovenous fistula.

Following a period of observation for 6 months, given progressive enlargement of the lesion the patient elected for surgical repair. Repair was undertaken in a sterile hybrid-operating suite, with the patient positioned in a slight reverse Trendelenburg position. The head was turned to the left and neck slightly extended with the use of a shoulder roll. The right neck and supraclavicular fossa, and the right leg were prepped to allow for autogenous great saphenous vein harvest. A supraclavicular incision was made to access the subclavian vein. The pseudoaneurysm was dissected free from the adjacent artery and brachial plexus, and following proximal and distal control the pseudoaneurysm was excised and the subclavian vein was repaired primarily. The patient recovered uneventfully and was discharged day 3 postoperatively. She was followed up 6 weeks postoperatively and had no recurrence or wound complications, and neurovascular examination of the right arm was normal.

Discussion

Venous aneurysms have been classified into 4 different types; congenital, acquired, pseudoaneurysms, and arteriovenous aneurysms. They can be morphologically described as either fusiform or saccular. ⁴ Pseudoaneurysms, in particular, can form as a result of focal vascular wall injury and extravasation of blood contained by the surrounding tissue. ⁵ Subclavian vein pseudoaneurysms are exceedingly rare with only a handful of cases reported in the literature.^6-11 Among these, traumatic or iatrogenic etiologies were uncommon, and penetrating trauma secondary to percutaneous biopsy has not been described; therefore, this case represents a novel mechanism of injury.

Most venous pseudoaneurysms are asymptomatic and present as an isolated, soft, painless mass. Those in the head and neck region often increase in size with a Valsalva maneuver, and those in the extremities demonstrate dependent characteristics—decreasing in size with limb elevation. ¹² Complications include thrombosis, pulmonary embolism, rupture, or mass effect and compression of adjacent structures. In the literature, thromboembolic events occur in up to 70% of lower limb venous aneurysms and have also been reported in central venous aneurysms.^13,14 There has been a single case of a subclavian vein aneurysm thrombosis complicated by bilateral pulmonary emboli requiring hospital admission. ¹¹

The initial diagnostic evaluation should be undertaken with duplex ultrasound. ⁵ Contrast-enhanced CT or MRI can better define the lesion’s anatomy and rule out the presence of an arteriovenous fistula. ¹⁵ Axial cross-sectional imaging can also aid surgical planning when preparing repair and reconstruction of the affected vein.

Management strategies vary depending on symptoms, anatomical location, size, patient preference, and risk of complications. Asymptomatic lesions can be appropriately managed nonoperatively with a “watch and wait” approach, whereas lower extremity and central venous pseudoaneurysms are typically managed surgically or endovascularly due to the potential for serious sequelae.^16,17 In this case, the patient opted for intervention, and open surgical repair was preferred due to the lesion’s accessible location, progressive growth, and patient’s young age. Endovascular techniques such as stenting or coil embolization have been described but are often reserved for lesions that are more difficult to access via open approach. ¹¹ Intraoperative decision-making involves the choice between primary repair, patch repair, ligation, or interposition grafting depending on the size and extent of the venous defect. Patients should always be prepped for autologous vein harvest if required, or a prosthetic interposition graft or patch may be utilised if there is no suitable conduit for reconstruction.

Conclusion

This case highlights a rare iatrogenic cause for a subclavian vein pseudoaneurysm resulting from axillary lymph node biopsy. It adds to the limited body of literature on venous pseudoaneurysm and supports open aneurysmorrhaphy as a safe and effective treatment option when performed by an experienced surgical team.