Neurofibromatosis type1(NF1) can involve any organ, but connective and nerve tissues are predominantly affected. Neurofibroma, Café-au-lait spot and osseous deformity are most common clinical findings. The real incidence of these abnormalities is indeed unknown because many lesions are undetected. Vasculopathy in NF1 mainly includes stenosis, occlusion, aneurysm, and arteriovenous malformation. Incidental findings or complications secondary to rupture or bleeding are the most reported modality in most literatures. Arterial lesions may be located in the aorta or in renal, mesenteric, carotid-vertebral or intracranial arteries, et al[7–9]. The causes described in these cases are variable and generally can be divided into two categories: bleeding by vascularized tumors of mesenchymal origin, such as ganglioneuromas or neurofibromas, and bleeding caused by rupture of weak medium to large-caliber arteries[10–12]. Vascular complications are the second most common cause of mortality in NF1 following after malignancy. The first report of vascular complications linked to neurofibromatosis was in 1945 when Reubi described changes in the renal artery of a patient with this disease. Right vertebral aneurysm in our case evolved with an extremely indolent growth over past three years. When the patient was firstly diagnosed as NF1, aneurysm of the right vertebral artery was neglected by MRI because of its small size. Three years later, the right-side lesion at C6 level was found and mistaken for neurofibroma because of the pain in the right upper limb. Intra-operative exploration demonstrated brachial plexus thickening, adhesion, interfascicular neurolysis, and no any evidence of neurofibroma. A series of radiculopathy in this patient, which possibly originated from the compression of the nerve bundle and aseptic inflammation by mass effect of vertebral aneurysm according to our speculation, was alleviated after the release of the nerve bundle. Therefore, establishing a diagnosis of neurofibroma must preclude the possibility of vascular lesion in those patients with NF1.
On the 3th day of post-surgery, the patient suffered rupture of the right internal thoracic artery aneurysm and subsequent mediastinal hematoma. This event was not related to recent surgery because aneurysm was located within the thoracic cavity. The reason of spontaneous rupture may be related to the increased vascular fragility due to arterial mesoderm dysplasia and elevated blood pressure due to postoperative stress. Three days after embolization of the internal thoracic artery, recurrent bleeding happened at the incision site. Based on the results of the initial DSA angiography, the rupture of the vertebral aneurysm may contribute to this disastrous event. Contrary to our anticipation, the right vertebral aneurysm did not rupture on second angiography, while the small aneurysm of the branch of the subclavian artery ruptured. According to our re-consideration for operative field, surgical iatrogenic injury was responsible for its formation and subsequent rupture. Signs and symptoms of vascular involvement in those patients with NF1 manifest as a wide spectrum based on its nature, usually including ischemic symptoms or mass effects from the affected artery. Clinicians must learn about its diverse clinical features. Synchronous vascular involvement of two different circulatory regions was found, and rupture happened at the short interval in our patient.
Current management for vasculopathy in NF1 includes open surgery and endovascular treatment[3, 10]. Surgical repair is aggressive and complex, and vessel reconstruction is also limited due to the fragile nature of the vessel wall and surrounding tissue. Endovascular treatments, such as coil transarterial embolization or percutaneous stent graft placement, are often considered preferable when it is mandatory to maintain an efficient blood flow in the regions perfused by the targeted vessel, which are less invasive, low intra-operative and post-operative mortality. In our patient, percutaneous arterial embolization was first utilized, then endovascular stent was implanted at the second time of bleeding from the incision site. Two procedures produced a satisfactory outcome. As literatures mentioned, endovascular treatment has currently become the preferred method and been shown to be an effective therapy in complicated circumstances. Surgical intervention should be reserved for use when minimal methods are not totally effective.
NF1-induced vasculopathy can occur anywhere in the human vascular system. Albeit with a low incidence, their possibility must be kept in mind when a patient with NF1 is examined even without obvious symptoms of vascular involvement. In the terms of diagnostic investigations, ultrasonography, CT angiography and MRI may help achieve early diagnosis of vascular involvement. Especially, vascular trees imaging monitored by one-stop CT angiography is easily available update. A routine vessel evaluation is strongly recommended for those patients with NF1. Combined with our experiences and lessons, it is vitally important to assess systemically great vessels in patients with NF1.
In conclusion, this case highlights synchronous multiple aneurysms of NF1 presenting with life-threatening aneurysm rupture after surgery. Contrast-enhanced CT precisely defines its location and anatomic relationship with adjacent organs. Additionally, endovascular treatment has become the mainstay for vascular lesions or aneurysm rupture in those patients with NF1.