Genetics of neurofibromatosis 1-associated peripheral nerve sheath tumors

Neurofibromatosis 1, an inherited disorder that affects 1/3500 individuals worldwide, predisposes to the development of benign and malignant peripheral nerve sheath tumors. The disorder results from inactivation of one of the NFI genes. The second NFI gene is typically inactivated in Schwann cells during tumor formation. This article reviews the different types of genetic alterations in NFI in both constitutional and tumor tissues and genetic alterations of other genes that may affect tumorigenesis. These studies have provided insight into the genetic basis of both the variable expression of the disorder and of benign and malignant peripheral nerve sheath tumorigenesis.     

Mesenteric involvement in neurofibromatosis type 1: CT and MRI findings in two cases

We report computerized tomographic and magnetic resonance imaging findings of neurofibromatosis type 1 with mesenteric involvement in two patients. The first patient was a 13-year-old female with a panmesenteric plexiform neurofibroma with segmental involvement of the bowel wall; she had a 3-year history of abdominal pain. The second patient was a 60-year-old female who presented with malignant transformation of multiple mesenteric neurofibromas 4 months after primary operation.     

A case of Miller-Dieker syndrome in a family with neurofibromatosis type I

The Miller-Dieker syndrome (type I lissencephaly) is a neuronal migration disorder which is associated with microdeletions in the short arm of chromosome 17. Neurofibromatosis type I (NF1) is an autosomal dominant condition associated with mutations in the long arm of chromosome 17, and characterised by neurofibromas, café-au-lait spots and axillary freckling. The neonatal period for a female infant born at 39 weeks gestation by emergency Caesarean section was complicated by frequent epileptic seizures as well as hypotonia. A computed tomography scan revealed evidence of lissencephaly, and chromosomal analysis showed a microdeletion on the short arm of chromosome 17 (17p13.3), confirming the diagnosis as Miller-Dieker syndrome. The child died at the age of 4 years and examination of the brain confirmed lissencephaly with a thickened cortex, deficient white matter, and grey matter heteropias. The mother had café-au-lait spots, and axillary freckling. In addition, the mother’s and maternal grandmother’s genetic analysis showed identical mutations in the neurofibromatosis I gene on the long arm of chromosome 17, confirming the diagnosis of NF1. The child did not possess the mutation. This case illustrates a rare neuronal migration disorder appearing in a child from a family with a history of NF1. Received: 15 April 1999 / Revised, accepted: 30 July 1999     

神经纤维瘤病的临床X线表现

本文报告了28例神经纤维瘤病,其中男15例,女13例。发现本病的临床X线表现可涉及颅脑、脊髓、胸部、腹部、四肢和软组织系统。X线表现为不同形式和性质。文内讨论了本病多系统病变和合并多种肿瘤特点。     

The different forms of neurofibromatosis

In the last two decades our knowledge of the natural history, genetics and management of the different forms of neurofibromatosis has changed. Of the numerical classifications of neurofibromatosis proposed in the past, only neurofibromatosis type 1 (Nf1) and neurofibromatosis type 2 (Nf2) have been shown to be distinct at clinical and molecular levels. Mosaicism has been demonstrated both in patients with Nf1 and in patients with Nf2, and features of segmental or mosaic Nf1 and Nf2 have been defined. The outlying phenotypes and the molecular genetics of other, rarer, types of neurofibromatosis have been delineated: these are hereditary spinal neurofibromatosis, Schwannomatosis, familial intestinal neurofibromatosis, autosomal dominant ”café-au-lait spots alone”, autosomal dominant ”neurofibromas alone”, Watson syndrome, Noonan/neurofibromatosis syndrome and the so-called syndrome of multiple naevi, multiple schwannomas and multiple vaginal leiomyomas. In this article I will review the different forms of neurofibromatosis, focusing on those aspects that most commonly challenge the neurosurgeon. Received: 3 February 1999     

MRI of Lumbar and Sacral Plexus Nerve Sheath Tumours

Seven patients with peripheral nerve sheath tumours affecting the lumbo-sacral plexus were examined with MR imaging utilizing a 1.5T magnet and spin echo pulse sequences. The majority of tumours were homogeneous in signal intensity and isointense with adjacent muscle on T₁ weighted images and showed markedly increased signal intensity on T₂ weighted images with central areas of relatively low signal intensity. An attempt to obtain a pathological correlation with the areas of low signal on T₂ weighted images was unsuccessful. The use of Gadolinium DTPA in one patient resulted in irregular enhancement of both a neurogenic sarcoma and smaller neurofibromas. The multiplanar imaging capabilities, high soft tissue contrast, non-invasiveness, lack of ionizing radiation and the characteristic appearance of neural tumours makes MR ideal for imaging these lesions.     

Malignant peripheral nerve sheath tumor of the back

A 65-year-old woman developed a tumor on the medial aspect of the lumbosacral spine. The diagnosis on biopsy was neurogenic sarcoma, T3N0M0. Despite wide surgical excision and regular follow-up, the patient developed a local recurrence requiring several supplementary operations before her death 4 years after the initial diagnosis. This case illustrates the highly aggressive and recurrent nature of these rare neurogenic tumors; they require early multidisciplinary management and regular careful follow-up. Received: 13 November 1999 / Accepted: 23 February 2000     

神经纤维瘤病I型的MRI研究

目的：回顾神经纤维瘤病I型（NF1）患者MRI表现，分析MR扫描序列及其诊断价值，以建立合适的MR成像方案，为NF1影像诊断提供有价值的依据。方法：对30例临床确诊为NF1患者采用本组MR成像方案进行扫描，主要包括：轴面SE序列T2WI；平扫矢状面SE脉冲序列T1WI；增强轴面或矢状面SE脉冲序列T1WI；轴面或冠状面液体衰减反转恢复（FLAIR）序列，同时分析病变的发病部位、数目、形态、信号的变化和病变的强化情况等。结果：MRI可见下列3种表现：（1）多发性脑内错构瘤：30例中25例在SE脉冲序列T2WI和FlAIR脉冲序列见高信号病灶，病灶主要位于苍白球、小脑和脑干。另外，25例中20例可见海马回、海马旁回等区晕状高信号改变。（2）视通道或下丘脑胶质瘤：视神经、视交叉增粗、扭曲；视交叉或下丘脑肿块，SE脉冲序列T2WI和FlAIR序列表现为不规则分叶状混杂信号肿块，在增强SE脉冲序列T1WI有明显不规则强化。（3）脊柱多发性神经纤维瘤：SE脉冲序列T2WI和脂肪抑制短时反转恢复（STIR）序列显示高信号沿脊神经分布的多发性肿瘤。结论：MRI能够作为1种 常规的影像检查方法对NF1患者进行诊断和追踪。本组MR成像方案能较好地显示NF1的多发性或多灶性病变。