Superior vena caval obstruction: a rare presentation of Behcet’s disease

Abstract

A 25-year-old Indian man presented with low-grade fever followed by gradually increasing swelling of neck and face. Physical examination showed bilateral neck swelling, facial swelling and dilated veins in the upper chest. Superior vena cava (SVC) obstruction due to an underlying malignancy was suspected. CT thorax showed large saccular aneurysm with thrombosis of bilateral subclavian arteries of which the right one caused external compression of right innominate vein draining into the SVC. A history of recurrent oral and scrotal ulcers was obtained following which skin pathergy test was done, which was suggestive of a diagnosis of Behcet’s disease (BD). He responded to treatment with steroids and azathioprine. This report illustrates that rare nonmalignant cause such as BD could also present with SVC obstruction.

Background

Superior vena cava (SVC) obstruction is mostly caused by advanced malignancy (80%–90%),¹ followed by indwelling catheters.² SVC obstruction is considered as a medical emergency and is a poor prognostic sign when caused by malignancy.

We report the case of a young man who presented with features of SVC obstruction. He was evaluated with a clinical suspicion of anterior mediastinal tumour. However, a thrombosed vascular aneurysm was found to be compressing the right innominate vein draining into SVC, the cause of which was found to be Behcet’s disease (BD).

Case presentation

A 25-year-old man working as a mechanic presented with low-grade fever of 1-month duration and 2 weeks history of bilateral neck and facial swelling. He was treated at a local centre with antipyretics and two courses of antibiotics with no improvement in his condition. He was a non-smoker and non-alcoholic and gave no significant medical or surgical history.

On physical examination, his vitals were stable. He had diffuse facial swelling, bilateral neck swelling and supraclavicular fullness, and dilated veins in the upper chest. A clinical diagnosis of SVC obstruction was made. An anterior mediastinal tumour such as lymphoma was thought to be the most probable cause, considering his age and presentation. On detailed interrogation revealed history of oral and scrotal ulcers, for which he sought treatment with native medications.

Investigations

Routine blood counts (neutrophils—82% and lymphocytes—18%), peripheral smear and liver and renal functions were normal. Acute phase reactants: erythrocyte sedimentation rate (21 mm) and C reactive protein (12 mg/L) were mildly elevated. Blood and urine cultures were sterile. Chest X-ray showed bilateral upper mediastinal widening with elevated right hemidiaphragm (figure 1). The three-dimensional volume-rendered CT image revealed bilateral subclavian aneurysm and the right saccular aneurysm of the subclavian artery, which was thrombosed, causing external compression of ipsilateral innominate vein draining into the SVC (figure 2) and collateral veins were seen over the chest wall (figure 3). The right elevated hemidiaphragm was thought to be due to phrenic nerve compression by the aneurysm. There was also aneurysmal dilatation of abdominal aorta—both supra and infra renal regions (figure 4). A diagnosis of BD was considered and skin pathergy test was performed and it was positive.

Figure 1.

Chest X-ray showing bilateral upper mediastinal widening with elevated right hemidiaphragm.

Figure 2.

Three-dimensional volume-rendered image showing bilateral subclavian artery aneurysm. Right subclavian artery aneurysm (arrow) noted compressing the ipsilateral innominate vein.

Figure 3.

Contrast enhanced axial CT showing collaterals along the right upper chest wall (white arrows).

Figure 4.

Three-dimensional volume-rendered CT showing multiple supra and infra renal aortic saccular aneurysms (white arrows). Prominent left accessory renal vein (arrowhead) draining into the left common iliac vein, secondary to compression of the left main renal vein by aortic aneurysm (thick arrow) at the same level.

Differential diagnosis

Initial presentation in this young male with SVC obstruction prompted us to consider the following anterior mediastinal tumours: lymphoma, thymoma and germ cell tumours.

In view of vascular aneurysm and history of orogenital ulceration, BD came up for consideration and skin pathergy test was ordered, which turned out to be positive and clinched the diagnosis.

Treatment

Treatment with high-dose oral steroids (initiated at 1 mg per kg body weight for 3 months and then gradually tapered) and azathioprine (initiated 50 mg two times per day orally gradually increased to 100 mg two times per day) and along with anticoagulation was commenced.

Outcome and follow-up

The patient had symptomatic improvement with reduced swelling and breathlessness after treatment and remained in remission during the 1-year follow-up.

Discussion

SVC obstruction was originally described by William Hunter in 1757 in a patient with a large syphilitic aortic aneurysm compressing the SVC.³ The most common causes in literature are thoracic malignancies;⁴ hence, most of the patients present to oncologists and pulmonary physicians.

BD is a multisystem inflammatory disease characterised by recurrent oral and genital ulcers along with uveitis and vasculitis.^{5 6} The disease is more prevalent in the ‘ancient silk route’, with the first case reported at Turkey in 1937.

Subclavian aneurysm causing external compression of superior vena cava without evidence of thrombosis is exceedingly rare in BD.⁵

The aetiology of BD is not clearly understood,⁷ the most widely accepted hypothesis is that it is a profound inflammatory response triggered by an infectious agent in a genetically susceptible host.⁸ The hallmark of the disease is recurrent oral and genital ulcers, which heals with scar.⁸ There is no specific diagnostic test or criteria. The most widely used is the International Study Group criteria.⁷ The vascular manifestations in BD predict the morbidity and mortality,⁹ the prevalence of which varies from 7.7% to 12.8%.^{10 11} It affects blood vessels of varying sizes and the venous system is involved more commonly than arteries.^{6 12} In the venous system, thrombosis especially in deep veins in lower limbs is the most common manifestation,⁹ it can also involve the vena cava. Aneurysms and pseudo aneurysms are seen in the arterial system, which could result in the dreaded complication of rupture.¹¹

The backbone of treatment is immunosuppression with steroids along with second line agents like azathioprine or mycophenolate, which cause significant regression of vascular lesions.^{11 13} Cyclophosphamide is also used in life-threatening vascular complications like pulmonary artery aneurysms.^{7 12} In recent years, there is increasing evidence for the role of biologicals¹⁴ in BD molecules like gevokizumab, anakinra, canakinumab, tocilizumab and rituximab¹⁴. These are not only used for mucocutaneous and ocular manifestations but have shown benefit in vascular lesions as well. The role of surgery is considered only in cases after acute inflammation has settled or in case of life-threatening aneurysms with impending rupture.⁹

Learning points.

• Superior vena cava obstruction can be due to causes other than malignancy and indwelling catheters.

• Behcet’s’ disease is a vasculitic disorder which is a rare cause of SVC obstruction, resulting from aneurysm of the subclavian artery casuing external compression.

• SVC obstruction in Behcet’s disease is mostly caused by venous thrombosis