|Year : 2014 | Volume
| Issue : 4 | Page : 270-272
A young lady with an intriguing limp: Solitary neurofibroma of the femoral nerve
Nagarjunakonda Venkata Sundarachary1, Amalakanti Sridhar2, Pokala Vijayalakshmi2, Inuganti Venkata Renuka3, Yekula Kiran Kumar4
1 Department of Neurology, Guntur Medical College, Guntur, Andhra Pradesh, India
2 Department of General Medicine, Guntur Medical College, Guntur, Andhra Pradesh, India
3 Department of General Surgery, Guntur Medical College, Guntur, Andhra Pradesh, India
4 Department of Pathology, Guntur Medical College, Guntur, Andhra Pradesh, India
|Date of Web Publication||10-Dec-2014|
FF-5, PG Hostel, Government General Hospital, Guntur, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Solitary neurofibromas are a part of neurofibromatosis. They are present in a variety of ways. We report a case of a solitary plexiform neurofibroma of the femoral nerve, which eluded diagnosis for 4 years.
Keywords: Femoral nerve tumor, imaging, plexiform neurofibroma, solitary tumor
|How to cite this article:|
Sundarachary NV, Sridhar A, Vijayalakshmi P, Renuka IV, Kumar YK. A young lady with an intriguing limp: Solitary neurofibroma of the femoral nerve. J NTR Univ Health Sci 2014;3:270-2
|How to cite this URL:|
Sundarachary NV, Sridhar A, Vijayalakshmi P, Renuka IV, Kumar YK. A young lady with an intriguing limp: Solitary neurofibroma of the femoral nerve. J NTR Univ Health Sci [serial online] 2014 [cited 2020 Apr 8];3:270-2. Available from: http://www.jdrntruhs.org/text.asp?2014/3/4/270/146643
| Introduction|| |
Neurofibromatosis type 1 (NF1) is a common inherited autosomal dominant disease with incomplete penetrance, reported in approximately 1 in 3000 individuals.  These tumors take on different morphologies, grow at variable rates and occur in multiple locations. Symptoms arise as neurofibromas enlarge, compressing and distorting local structures. Of all the manifestations of neurofibromatosis, plexiform neurofibroma is one of the most difficult to treat.  We present a unique case of a solitary plexiform neurofibroma of the femoral nerve.
| Case report|| |
The present case report is about a 40-year-old woman came with the chief complaints of dragging type of pain and swelling of right lower limb since 5 years, low back pain radiating to right lower limb along the medial border of the right leg since 2 years, a lump over the upper part of right buttock since 2 years and painful limping gait since 4 months. Her pain increased on standing and on walking and relieved on walking for a long distance and on lying onto the right side. Her pain was relieved on standing and stooping forward. Pain was more during the night. She had developed a tingling sensation over right medial three toes since the last 2 months. There was no weakness of lower limbs. There was no loss of sacral sensations. There was no history of any bladder or bowel involvement. There was no history of fever. There was no history of trauma. There was no history of loss of weight or appetite.
Lumbar hyperlordosis was present. She held her right leg in flexion and intorsion at the hip and flexion at the knee. Movements at all joints were normal. Straight leg raising test was negative. Patrick test was negative. Neurological examination was completely normal. Complete blood examination was normal. Rheumatoid factor and anti-nuclear antibody was negative. Ultrasonography abdomen and X-ray pelvis revealed no abnormality.
She was evaluated previously by two other doctors separately; magnetic resonance imaging (MRI) of the lumbar spine [Figure 1] and MRI of pelvis [Figure 2] revealed no abnormality.
|Figure 2: Magnetic resonance imaging pelvis does not show any abnormality|
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Since the neurological examination was normal we concluded that there must be a musculoskeletal cause. Based on the history and examination, it was clear that the pathology was above the right hip and below the lumbar plexus. Therefore, we got a computed tomography scan with contrast of the abdomen and pelvis [Figure 3] carried out. It showed a mass lesion of heterogeneous density in the right iliac fossa displacing the psoas anteriorly involving the iliacus extending into right paravertebral region. MRI pelvis with contrast [Figure 4] revealed a 7.5 cm × 2.5 cm mass in the right iliac fossa causing anterior displacement of the psoas muscle abutting the iliac vessels.
|Figure 3: Computed tomography abdomen shows heterogeneous mass behind the right psoas muscle|
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|Figure 4: Magnetic resonance imaging with contrast of abdomen shows mass behind right psoas|
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Intra-operatively the mass was found to be originating from the right femoral nerve in the iliac fossa. The mass along with the femoral nerve were excised. Biopsy [Figure 5] of the mass revealed features suggestive of a plexiform neurofibroma. Post-operatively, apart from clumsiness in walking due to resection of the femoral nerve, the patient recovered well. The agonizing pain of 5 years was alleviated, but extensor muscle weakness developed due femoral nervectomy. Retrospective examination for features of neurofibromatosis revealed no other lesion in her body.
|Figure 5: Histopathological specimen shows features of plexiform neurofibroma|
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| Discussion|| |
Neurofibromas are benign nerve sheath tumors, which present in three forms; local discrete, generalized neurofibromatosis and plexiform neurofibromas. Common sites of occurrence of plexiform neurofibroma are fifth cranial nerve and extremities. Plexiform neurofibromas are diffuse enlargements of multiple fascicles of the nerves and its branches, leading to thickening of nerves. They grow along nerves extending into the surrounding tissue. They are slow growing and locally infiltrating benign tumors. When located deeply they may have a greater chance of malignancy. 
The mass eluded detection for due to its unusual location. The MRI lumbar spine was taken up to the S1 vertebra and so could not reveal the mass, which was below that level. The first MRI pelvis showed images just below the mass and hence the diagnosis was missed.
The term "plexiform neurofibroma" is used to describe a network like growth of tumor involving multiple fascicles of a nerve, leading to a diffuse mass of thickened nerve fibers surrounded by proteinaceous matrix.  Plexiform neurofibroma may occur with incidence of 25-50% respectively. Mild or segmental forms of NF1 may be caused by somatic mosaicism, a hypothesis that has been put forward to explain the development of isolated plexiform neurofibromas in the absence of other NF1 manifestations.  They account for substantial morbidity, including disfigurement, functional impairment and may even be life-threatening.  In our case, the patient suffered with a limp and painful limb for 4 years. Solitary plexiform neurofibroma involving only the femoral nerve is extremely rare.
Surgical excision is the primary option for plexiform neurofibromas.  Pegylated interferon α-2b, phenylacetate, phenylbutyrate, tipifarnib, pirfenidone all being tried as pharmacological therapies for neurofibromas, but they are still elusive to our patients in India.
About 10% of plexiform neurofibromas undergo transformation into a malignant peripheral nerve sheath tumor.  Therefore, surgical excision was mandatory in our patient.
This case instructs the importance of persistence in the evaluation of a clinical presentation in spite of unfruitful sophisticated investigations.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]