Dural Ectasia in Neurofibromatosis 1: Case Series, Management, and Review

RASopathies for Radiologists

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Video-Assisted Thoracoscopic Lateral Interbody Fusion for Symptomatic Pseudarthrosis in Neurofibromatosis 1-Associated Spinal Deformity

BACKGROUND

The treatment of symptomatic pseudarthrosis via posterior-only approaches in the setting of neurofibromatosis 1 (NF1) is challenging due to dural ectasias, resulting in erosion of the posterior elements. The purpose of this report is to illustrate a minimally invasive method for performing anterior thoracic fusion for pseudarthrosis in a patient with NF1-associated scoliosis and dysplastic posterior elements. To the best of our knowledge, this is the first documented case of using video-assisted thoracoscopic lateral interbody fusion to treat pseudarthrosis for NF1-associated spinal deformity.

CASE DESCRIPTION

The patient underwent video-assisted thoracoscopic anterior spinal fusion via a direct lateral interbody approach with interbody cage placement at T10-T11 and T11-T12, followed by revision of his posterior spinal fusion and instrumentation. The patient had an uneventful postoperative course. At 6 months of follow-up, the patient had complete resolution of his preoperative symptoms and had returned to full-time work with no complaints. At 3 years postoperatively, the patient reported being satisfied with the operation and had continued to work full-time without restrictions.

CONCLUSIONS

To the best of our knowledge, this is the first report of pseudarthrosis in the setting of NF1-associated scoliosis treated via minimally invasive anterior thoracic fusion facilitated by video-assisted thoracoscopic surgery. This is a powerful technique that allows for safe access for anterior thoracic fusion in the setting of dysplastic posterior anatomy and poor posterior bone stock.

Dural ectasia with cauda equina syndrome, a rare case report

INTRODUCTION AND IMPORTANCE

Dural ectasia, which is often idiopathic, is seen both in patients with neurofibromatosis and Marfan's syndrome. In neurofibromatosis, the ectasia is most often seen in the thoracic region but can occur at any point along the dura. A complication such as cauda equina syndrome is usually rare.

CLINICAL PRESENTATION

A 48 year old male complaining of recurrent throbbing headache, for 3 years, 2 years ago he developed progressively lower back pain, associated with numbness and tingling sensation of the lower limbs. A year ago he experienced defecation and urinary incontinence. On further questioning the patient reported to have first degree relative with neurofibromatosis. On examination he has multiple café au laite on the trunk, back and left arm, and plexiform on the left palm, mild right deviation on thoracic region on the back. Lower limb muscle power grade 4/5 bilaterally, sensation was intact. Laboratory work up Full blood counts, electrolytes, renal and liver function tests were normal, MRI of the lumbar spine demonstrate L3/L4 and L4/l5 mild disc bulge with no significant narrowing of the primary canal and no evidence of existing nerve root impingement, increase antero-posterior diameter of dura sac involving L5-S1, with a Dural Sac Diameter of S1 increased compared to that of L4 with mild scalloping of lower lumbar vertebra and pronounced at S1 vertebral body. A diagnosis of cauda equina syndrome and dural ectasia secondary to neurofibromatosis was rendered. Lumbar peritoneal shunting, was reached as a surgical treatment for this patient, but due to inadequate and unavailability of the required shunting equipment, the patient was managed conservatively with anti- inflammatory medications, lumbar CSF tapping, genital hygiene and counselling. 3 months of follow up, the patient was able to walk, with power 5/5 to both lower limbs, however fecal and urine incontinence persisted.

DISCUSSION

this case was particularly unusual due to the combination of cauda equina syndrome and dural ectasia, Dural ectasia is seen with various conditions including Marfan syndrome, Ehlers-syndrome, neurofibromatosis 1, Ankylosing spondylitis, trauma, scoliosis or tumors it may also have no clear cause. In most cases patients with dural ectasia are asymptomatic few may present with low back pain, radicular pain in the buttocks or legs and headache and rarely caudal equina syndrome. The management of dura ectasia may be conservative for asymptomatic patient and for a symptomatic patient surgery such as stabilization, marsupialization and lumbar peritoneal shunt.

CONCLUSION

Dural ectasia with cauda equina syndrome are rarely complication of neurofibromatosis. Familiarity with its classic imaging and clinical features as described in this case report can help its early detection and management.

Management of Tarlov cysts: an uncommon but potentially serious spinal column disease-review of the literature and experience with over 1000 referrals

Tarlov cysts were thought to be anatomic variants of uncertain etiology and clinical significance when initially described over 80 years ago. They are often detected in routine lumbosacral imaging and generally not reported in a differential diagnosis. There is increasing evidence that at least some Tarlov cysts are symptomatic and can have a significant adverse impact on patients' health and well-being. Women are disproportionately affected with this condition, often presenting with long-standing pain and neurological dysfunctions. Significant gender bias has been a concern in the management of these patients. Unfortunately, there is no consensus on patient selection or management approaches for symptomatic Tarlov cysts. This review article updates information on the prevalence, diagnosis, clinical significance, and treatments of these cysts. Based on these findings and experience with over 1000 patient referrals, a treatment decision algorithm for symptomatic Tarlov cysts was constructed to provide guidance for appropriate management of patients with these complex cysts.

Intrasacral meningoceles: Clinical presentation, surgical management, and postoperative outcome: The Giannina Gaslini Hospital's experience

INTRODUCTION

Intrasacral meningoceles are cysts associated with herniating arachnoid with no nerve root within due to an area of weakness of the dura mater. They are thought to be congenital, but they are usually not symptomatic until adulthood. Surgical treatment is generally indicated in the presence of symptoms.

METHODS

We selected cases belonging to the IB category of Nabors et al.'s classification who underwent surgery between 2008 and 2021 at Giannina Gaslini Hospital. Exclusion criteria were prior history of trauma, infections, or operations. Patients' clinical details, associated conditions, surgical techniques, peri- and postoperative complications, and outcomes were collected retrospectively from clinical charts. We compared our series to literature: keywords "intrasacral meningocele" were used on the search engine MEDLINE - Pubmed.

RESULTS

We identified 23 cases: 5 of the 14 symptomatic patients had a complete resolution, and 5 had a substantial clinical improvement after surgery. Cyst recurrence and major postoperative complication occurred in none. Among 59 articles considered for evaluation, 50 were excluded and remaining 9 articles underwent full-text analysis.

DISCUSSION AND CONCLUSION

The pathogenesis of instrasacral meningoceles is still not completely understood and the spectrum of symptoms is wide. A posterior surgical approach with sacral laminectomy is preferred, although in selected cases it is possible to perform a supplemental anterior approach (sometimes endoscopic). In our surgical series, the largest one published in the literature, a good clinical outcome was achieved in most patients with no cyst's recurrence, pointing out the importance of surgical interruption of communication between cyst and subdural space.

Familial and syndromic forms of arachnoid cyst implicate genetic factors in disease pathogenesis

Arachnoid cysts (ACs) are the most common space-occupying lesions in the human brain and present significant challenges for clinical management. While most cases of ACs are sporadic, nearly 40 familial forms have been reported. Moreover, ACs are seen with increased frequency in multiple Mendelian syndromes, including Chudley-McCullough syndrome, acrocallosal syndrome, and autosomal recessive primary ciliary dyskinesia. These findings suggest that genetic factors contribute to AC pathogenesis. However, traditional linkage and segregation approaches have been limited in their ability to identify causative genes for ACs because the disease is genetically heterogeneous and often presents asymptomatically and sporadically. Here, we comprehensively review theories of AC pathogenesis, the genetic evidence for AC formation, and discuss a different approach to AC genomics that could help elucidate this perplexing lesion and shed light on the associated neurodevelopmental phenotypes seen in a significant subset of these patients.

Multidisciplinary approach for repair of a large ventral thoracic meningocele in neurofibromatosis-1; a systematic review of the literature and case report

Thoracic meningoceles and dural ectasia are less commonly recognized manifestations of neurofibromatosis 1 (NF1). Rarely, large thoracic meningoceles may become compressive and lead to respiratory compromise secondary to lung compression. Surgical goals aim to increase lung aeration through decreasing the size of the meningocele through shunting, excision or repair of the meningocele, and varying degrees of dural tube reconstruction. There is no agreement on the best approach for large, symptomatic meningoceles. Here, we discuss the case of a 41-year-old woman with NF1 who presented with dyspnea and enlargement of a large, 19 cm thoracic meningocele. A multidisciplinary team of thoracic, plastic, and neurological surgery participated in the operation to excise the meningocele and reconstruct the dural tube without the need for subsequent shunting of spinal fluid. We also systematically review the literature on thoracic meningoceles in NF1 to understand the optimal treatment of this pathology.