Severe Thoracic and Spinal Bone Abnormalities in neurofibromatosis type 1
Introduction
Neurofibromatosis type 1 (NF1) is one of the most frequent autosomal dominant disorders, characterized by neurofibromas, “café-au-lait” spots, axillary or groin freckling, Lisch nodules, optic pathway glioma and skeletal lesions [Ferner, 2010]. Classical skeletal abnormalities encompass sphenoid wing dysplasia, congenital bowing of the long bones, respectively described in about 1% and 2% of NF1 patients and vertebral osteopathy associated with non-dystrophic or dystrophic scoliosis found in about 10% of NF1 patients [Ferner, 2010]. Characteristic features of dystrophic scoliosis include vertebral scalloping, rib penciling, vertebral wedging, absence or hypoplasia of the vertebral pedicles and intervertebral foraminal enlargement [Zhao et al., 2015]; [Alwan et al., 2005].
The defects in bone observed in NF1 patients are due to the loss of both copies of NF1 in osteoclasts and/or osteoblasts. Increased osteoclastic activity and impaired osteoblastic function have been demonstrated in several strains of Nf1 conditional knockout mice, used in particular to model dystrophic scoliosis [Wang et al., 2011]; [He et al., 2012]. In addition controversial theories explaining the determinism of dystrophic scoliosis include potential primary causes (i.e. primary mesodermal dysplasia, osteomalacia) and secondary causes related to intraspinal anomalies, responsible for mechanical stresses, like erosion of bone by localized neurofibromas and dural ectasia [Tsirikos et al., 2005]. We present here severe thoracic and spinal bone deformities observed in a patient affected by NF1.
Section snippets
Case report
The proband, a 17-year-old boy, was the second child from non-consanguineous healthy parents. Family history was uninformative. Pregnancy was uneventful, especially, all ultrasound exams were considered normal. Delivery at 40 weeks of gestation was marked by transitory moderate respiratory difficulties (APGAR 5/10) and the discovery of severe chest and spine deformations. During his early first hours of life, the patient presented with an acute respiratory distress requiring invasive
Discussion
The molecularly confirmed NF1 patient presented here had extreme severe spinal and thoracic malformations affecting bone and lung tissues, corroborating the single recently described similar NF1 patient suffering from the same association of severe scoliosis and chest deformity leading to respiratory insufficiency [Francis et al., 2015]. Moreover spine CT showed different types of abnormalities, including fusion of vertebral bodies, which are not typically associated with NF1 bony dysplasia.
References (9)
- et al.
Is osseous dysplasia a primary feature of neurofibromatosis 1 (NF1)?
Clin. Genet.
(2005) - et al.
The characteristics of thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis
J Bone Jt. Surg Am
(2003) The neurofibromatoses
Pract. Neurol.
(2010)- et al.
Severe spinal and chest deformity secondary to neurofibromatosis
Can. J. Anesth. Can. Anesth.
(2015)
Cited by (10)
Sectional Correction Technique in Dystrophic Scoliosis Secondary to Neurofibromatosis Type 1: A Comparison with Traditional 2-Rod Correction Technique
2022, World NeurosurgeryCitation Excerpt :A loss of surgical correction appears to be common after surgery. In such cases, correcting the deformity due to NF1 dystrophic scoliosis remains challenging.13,24,25 In both groups, the main curve Cobb angle, CBD, AVT, TK, LL, and SVA were significantly improved postoperatively.
RASopathies: The musculoskeletal consequences and their etiology and pathogenesis
2021, BoneCitation Excerpt :Non-dystrophic scoliosis is the more common of the two, usually presenting in early adolescence, with similarities in presentation and treatment approach to idiopathic scoliosis in the general population. In contrast, dystrophic scoliosis, described as “a short-segment, sharply angulated curve associated with underlying vertebral-body and rib abnormalities and sometimes with adjacent plexiform neurofibromas” [5] is apparent in earlier childhood (ages 6–10 years) [6], can be more rapidly progressive, at times associated with respiratory impairment [20], and typically requires surgical correction [5,13,21]. Unfortunately, for a given individual, modulation between non-dystrophic and dystrophic scoliosis can also occur [10,22]; hence a true distinction between the two types may be inexact.
Grade V Thoracic Spondylolisthesis in Neurofibromatosis Type 1: Case Report and Literature Review
2020, World NeurosurgeryCitation Excerpt :In this study, the case showed neurologic deficit, possibly due to compression. Spondylolisthesis as a spine deformity has been described in NF-1 patients, but most cases present a lumbosacral location.6,7,26 The case in this study showed grade V T2 spondylolisthesis with T2-T5 autofusion, and autofusion of vertebral bodies was not typically associated with NF-1 bony dysplasia.26
Neurofibromatosis: analysis of clinical cases and new diagnostic criteria
2022, Nervno-Myshechnye Bolezni