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CASE REPORT Table of Contents  
Ahead of print publication
Plexiform neurofibromas of bilateral brachial and lumbosacral plexuses


 Department of Neurology, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India

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Date of Submission05-Feb-2022
Date of Decision24-May-2022
Date of Acceptance13-Jun-2022
Date of Web Publication13-Jul-2022
 

  Abstract 

Plexiform neurofibroma is a peripheral nerve sheath tumor that involves multiple nerve fascicles or nerve branches and is considered to be pathognomic of neurofibromatosis type-1. They are often large lesions which can distort the nerves and are most commonly reported in the craniomaxillofacial region. We are reporting plexiform neurofibroma of bilateral brachial and lumbosacral plexuses, which is rarely reported, with only three cases being reported so far. A 33-year-old woman presented with complaints of dragging of the right lower limb on walking, for the past 6 months and on examination, was noted to have features of cervical myelopathy. Magnetic resonance imaging of the spine showed multiple lesions of the cervical exiting nerve roots bilaterally, with extension along the brachial plexus and lesions along the lumbar plexus on both sides suggestive of plexiform neurofibroma. Considering the lack of feasibility of complete resection, surgery was not considered and she was advised to be under follow-up. Plexiform neurofibromas are large lesions arising from peripheral nerves and can cause symptoms due to the compression of adjacent structures. Plexiform neurofibroma involving brachial and lumbosacral plexuses on both sides is very rarely reported, with only three cases being reported so far.

Keywords: Brachial plexus, compressive myelopathy, lumbosacral plexus, plexiform neurofibromas


How to cite this URL:
Sheetal S, Vijayalekshmi S, Sasidharan A, Merin Joy N J. Plexiform neurofibromas of bilateral brachial and lumbosacral plexuses. Apollo Med [Epub ahead of print] [cited 2022 Sep 27]. Available from: https://apollomedicine.org/preprintarticle.asp?id=351224



  Introduction Top


Plexiform neurofibroma is a benign tumor of peripheral nerves, which can grow to very large sizes.[1] It is considered to be pathognomic of neurofibromatosis type-1 (NF-1) and is seen in 30% of the cases. The clinical presentations are variable, depending on the location of the tumor. They usually present with the features of compression of adjacent structures. We report a case of plexiform neurofibroma, arising from brachial and lumbosacral plexuses on both sides, with only three similar cases reported till date.


  Case Report Top


A 33-year-old woman presented with complaints of dragging of the right lower limb on walking for the past 6 months. She had difficulty in climbing stairs and putting on left footwear and experienced twisting of the left ankle repeatedly. She had precipitancy of micturition for the past 6 months. She had no symptoms referable to any other limbs and no sensory symptoms. On examination, she had multiple café au lait spots (>6), spasticity involving bilateral lower limbs, grade 5/5 power in all limbs, exaggerated deep-tendon jerks bilaterally, with bilateral extensor plantar. The sensory system examination was normal.

Magnetic resonance imaging (MRI) of the spine showed multiple nodular lesions of the cervical exiting nerve roots bilaterally, exhibiting T1 isointense and T2/STIR hyperintense signals, with extension along the nerve roots, trunks, divisions, and cords of the brachial plexus [Figure 1]a and [Figure 1]b. Similar elongated lesions were seen in the spinal canal along C1 and C4 roots, causing compression of the cord [Figure 1]c. Multiple T2 hyperintense nodular lesions were seen along the lumbar plexus on both sides, with some lesions exhibiting central hypointensity and peripheral hyperintensity, referred to as the target sign [Figure 2]a. A T2 hyperintense lesion was seen in the spinal canal at L5 level in the region of the left traversing L5 nerve root [Figure 2]b. Hence, the possibility of plexiform neurofibroma was considered. On reviewing the family history, her daughter had multiple cutaneous neurofibromas over the neck. She declined biopsy from the lesion and genetic testing for NF-1. Considering the potential morbidity from attempting surgical resection, in the setting of extensive lesions, no surgery was undertaken and she was advised 6 monthly follow-up visits.
Figure 1: (a and b) Coronal T2 weighted magnetic resonance imaging showing hyperintensity, irregularity and enlargement of the brachial plexuses bilaterally (c) Sagittal T2 weighted MR images showing compression of the spinal cord at the C1 and C4 level. MR: Magnetic resonance

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Figure 2: MRI of the lumbar spine (a) Coronal T2 images showing multiple T2 hyperintense nodular lesions along lumbar plexus bilaterally, with some lesions exhibiting central hypointensity and peripheral hyperintensity- the target sign. (b) Sagittal T2 images showing a T2 hyperintense lesion seen in the spinal canal at L5 level. MRI: Magnetic resonance imaging

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  Discussion Top


Plexiform neurofibroma is a benign tumor of peripheral nerves and is considered pathognomonic of NF-1. Since our patient had evidence of plexiform neurofibroma and multiple café au lait spots (>6), she satisfied the criteria for NF-1 as per the National Institutes of Health Diagnostic Criteria.[2] In contrast to cutaneous neurofibroma, plexiform neurofibromas are deeper lesions affecting nerves and plexus. Plexiform neurofibroma of bilateral brachial and lumbosacral plexuses, as shown in our patient, is rarely reported, with only three cases being reported so far.[3],[4],[5] On MRI, they appear isointense on T1 sequences, and hyperintense on T2 sequences with typical target-like appearance due to the central fibrous tissue surrounded by the myxoid tissue.[1] On MRI, these lesions should be differentiated from plexiform schwannoma, which appears hypo to isointense on T1, and heterogeneously hyperintense on T2 and may demonstrate target sign.[6] Another radiological differential diagnosis is hemangioma, which shows slight hyperintensity on T1 and T2, and “light bulb sign.”[6] Plexiform neurofibromas can also extend into surrounding structures, causing symptoms of compression. Cervical cord compression by cervical nerve root neurofibromas has been rarely reported.[7],[8] Recent reports on patients plexiform neurofibromas not amenable to surgery, have shown the advantage from long-term treatment with oral selumetinib, which is an inhibitor of MAPK kinase 1 and 2.[9] Surgical procedures should be performed only when there is a significant functional compromise, deformity, or intractable pain and if a nearly complete resection seems possible along with preservation of neurological function.[4]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding

Nil.

Authors contribution

Dr. Sheetal S: conception of the idea, drafting the article, Critical revision of the article and Final approval of the version to be published. Dr. S Vijayalekshmi: Critical revision of the article and Final approval of the version to be published. Dr. Aswathy Sasidahran: Critical revision of the article and Final approval of the version to be published. Dr Jisa Merin Joy.N: Critical revision of the article and Final approval of the version to be published.



 
  References Top

1.
Sheetal S, Thomas R, Sasidharan A, Vijayalekshmi S. Plexiform neurofibroma: An uncommon cause of back pain. Indian J Pain 2021;35:87-8.  Back to cited text no. 1
  [Full text]  
2.
Ferner RE, Huson SM, Thomas N, Moss C, Willshaw H, Evans DG, et al. Guidelines for the diagnosis and management of individuals with neurofibromatosis 1. J Med Genet 2007;44:81-8.  Back to cited text no. 2
    
3.
Warade C, DesaiK I. Bilateral plexiform neurofibromatosis involving brachial plexus and lumbosacral plexus. Indian J Neurosurg 2020;9:233-5.  Back to cited text no. 3
    
4.
Kumar A, Devi BI. Enigma in management of plexiform neurofibromas of bilateral brachial and lumbosacral plexuses: Shall we let nature take its course? Neurol India 2019;67:S154-6.  Back to cited text no. 4
[PUBMED]  [Full text]  
5.
Souza FH, Dabdoub CB, Bernardino SN, Silveira EN, Litvin S, Azevedo-Filho H. Bilateral plexiform neurofibromas of the brachial and lumbosacral plexuses. Arq Neuropsiquiatr 2013;71:128-30.  Back to cited text no. 5
    
6.
Ieong CM, Kong SC. Diagnosis of plexiform schwannoma of the foot in a 66-year-old male: A case report and literature review. AME Case Rep 2020;4:34.  Back to cited text no. 6
    
7.
Leonard JR, Ferner RE, Thomas N, Gutmann DH. Cervical cord compression from plexiform neurofibromas in neurofibromatosis 1. J Neurol Neurosurg Psychiatry 2007;78:1404-6.  Back to cited text no. 7
    
8.
Barber DB, Quattrone BE, Lomba ME, Able AC. Neurofibromatosis: An unusual cause of cervical myelopathy. J Spinal Cord Med 1998;21:148-50.  Back to cited text no. 8
    
9.
Dombi E, Baldwin A, Marcus LJ, Fisher MJ, Weiss B, Kim A, et al. Activity of selumetinib in neurofibromatosis type 1-related plexiform neurofibromas. N Engl J Med 2016;375:2550-60.  Back to cited text no. 9
    

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Correspondence Address:
S Sheetal,
16 FG, The Edge, Skyline apartments, Thirumoolapuram, Thiruvalla - 689 115, Kerala
India
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/am.am_22_22



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