Sudden death due to rupture of the right internal carotid artery in neurofibromatosis type 1: A case report

Vascular involvement is a well-recognized manifestation of neurofibromatosis type 1 (NF1) which has the potential to be fatal when disrupted. We here present a case of sudden death due to the fatal arterial rupture resulted from infiltration of the neurofibromas. A 42-year-old man who suffered from NF1 presented a 1-h history of sudden onset of pain in his right cervical region. His condition worsened and became unconscious on his way to the emergency room. Despite resuscitation efforts, he died 30 min later without regaining consciousness. Autopsy examination showed that a neurofibroma located around the right internal carotid artery, confirmed immunohistochemically with S-100, vimentin and CD34. Furthermore, proliferation of spindle cells positive for S-100 was seen in the wall of right internal carotid artery, which was disrupted and resulted in a hemorrhage. These findings suggest that the artery was disrupted by neurofibromas in the vascular wall, which led to fragility of the vessel. On the basis of these findings, we concluded that the cause of death was asphyxia resulting from airway obstruction compressed by the hematoma due to the arterial rupture. As the locality of the neurofibroma and hemorrhage were closed to the carotid baroreflex, we considered another possible mechanism of his sudden death, which could be cardiac inhibition induced by vagal stimulation. We hope this case will increase recognition of NF-1 vasculopathy when encountering any sudden death in NF1 patients.     

Dermoscopy of the iris: identification of Lisch nodules and contribution to the diagnosis of neurofibromatosis type 1

Neurofibromatosis is a common genodermatosis, whose diagnosis often involves the participation of a dermatologist. A case of a 38-year-old female patient with four café-au-lait macules and eleven neurofibromas on clinical examination is presented. Dermoscopy allowed the identification of Lisch nodules in the iris, bilaterally. The combination of these findings allowed the diagnosis of neurofibromatosis type 1, according to NIH criteria. Lisch nodules are melanocytic hamartomas of the iris, which must be evaluated through a visual augmentation method, usually employed in ophthalmology. Alternatively, dermoscopy can be used and contribute to the early diagnosis of neurofibromatosis type 1.     

Awake craniotomy for assisting placement of auditory brainstem implant in NF2 patients

Objectives: Auditory brainstem implants (ABIs) may be the only opportunity for patients with NF2 to regain some sense of hearing sensation. However, only a very small number of individuals achieved open-set speech understanding and high sentence scores. Suboptimal placement of the ABI electrode array over the cochlear nucleus may be one of main factors for poor auditory performance. In the current study, we present a method of awake craniotomy to assist with ABI placement.

Methods: Awake surgery and hearing test via the retrosigmoid approach were performed for vestibular schwannoma resections and auditory brainstem implantations in four patients with NF2. Auditory outcomes and complications were assessed postoperatively.

Results: Three of 4 patients who underwent awake craniotomy during ABI surgery received reproducible auditory sensations intraoperatively. Satisfactory numbers of effective electrodes, threshold levels and distinct pitches were achieved in the wake-up hearing test. In addition, relatively few electrodes produced non-auditory percepts. There was no serious complication attributable to the ABI or awake craniotomy.

Conclusions: It is safe and well tolerated for neurofibromatosis type 2 (NF2) patients using awake craniotomy during auditory brainstem implantation. This method can potentially improve the localization accuracy of the cochlear nucleus during surgery.     

Cerebellar gliomas in children with NF1: pathology and surgery

Cerebellar gliomas associated with NF1 (CGNF1) are rarely reported in the literature, and they are considered to be malignant in a high proportion of cases. In an attempt to improve the definition of this disease and clarify its management, we reviewed our patients with CGNF1 and compared their tumors with sporadic cerebellar gliomas (SGC). We operated on six children with CGNF1, all but one of whom were asymptomatic. They represented one-tenth of all pediatric cerebellar gliomas, and one third of NF1- associated gliomas seen in our institution. CGNF1 appeared at a later age than SCG. They are seated near the roof of the IV ventricle and are not related to white matter hypersignal hamartomas. Most of these tumors showed radiological progression. They were four pilocytic astrocytomas, one ganglioglioma, and one malignant astrocytoma. One patient had tumor recurrence after 8 years, and the others are still disease free. The overall outcome appeared to be better for GCNF1 than for SCG. On account of the regular growth, uncertain pathology, and good surgical outcome, we advocate systematic resection of these tumors. Received: 7 February 2000