Tag Archives: neurofibromatosis

Case study: Schwannoma of the tibial nerve in a patient with a history of neurofibromas

by Zachary T. Ritter, DPM, MS, FACFAS1*, Amy Kruger, DPM2

The Foot and Ankle Online Journal 12 (3): 6

A schwannoma is a common benign tumor of the peripheral nerve sheath.  Schwannomas are rarely found in the foot and typically do not elicit any painful symptoms. We report the case of a large schwannoma eliciting tarsal tunnel like symptoms in a patient with a previous history of neurofibromatosis within the spine. The patient had previously undergone lumbar laminectomy for neurofibromas of the lumbar spine that went on to develop pain in the right foot.  She then underwent extensive workup of this persistent right foot pain. She was treated for plantar fasciitis for several years, until presenting to our clinic. At that time, EMG findings showed tibial neuropathy and medial plantar nerve degeneration; accompanied by MRI findings consistent with a schwannoma of the tibial nerve. The patient underwent surgical excision of the mass. The pathology report revealed an encapsulated biphasic tumor composed of compact hypercellular areas and mixed hypocellular areas with foci of hyalinization with no malignant features measuring 3.7 x 2.5 x 2.0 cm, consistent with a diagnosis of schwannoma.  The patient had an uneventful postoperative course. At one year follow up, she was pain free but had persistent neuropathic changes to the distal forefoot. Currently, there are few reports in the literature of schwannomas arising the tibial nerve eliciting the symptoms of tarsal tunnel syndrome. The incidence of such a schwannoma in association of a patient with a history of neurofibromas is even more rare.

Keywords: neuroma, schwannoma, neurofibromatosis, plantar fasciitis

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0006

1 – Chief of Podiatric Surgery. UPMC Susquehanna. Williamsport, PA.
2 – PGY-3. St. Luke’s University Hospital. Bethlehem, PA.
* – Corresponding author: ztritter@msn.com


A schwannoma is a benign soft tissue tumor of the peripheral nerve sheath. These slow-growing tumors can be difficult to distinguish from other benign tumors based on clinical findings [1]. The principal diagnosis is made histologically by by identifying the principle cellular elements—Schwann cells. This tumor was first described in the thorax [2], and is typically found in the head, neck, and flexor surfaces of the extremities [3]. The most common nerve affected is the eighth cranial nerve; however, the spinal roots as well as the sympathetic, vagus , ulnar, and peroneal nerves are commonly affected as well [3,4]. This tumor is rarely found in the tibial nerve in the region of the tarsal tunnel [5-9]. Finally it is highly uncommon to find this tumor in association with a neurofibroma, with only one report of a schwannoma of the posterior nerve accompanied by a neurofibroma in the tarsal tunnel itself [10]. There are currently no other reports of a patient with a schwannoma eliciting secondary tarsal tunnel syndrome in a patient with a history of symptomatic neurofibromas elsewhere in the literature.

We report a case of a large schwannoma of the tibial nerve located in the tarsal tunnel in a patient with a previous history of neurofibromas in the spine.

Case Report

A 69-year-old female presented to UPMC Susquehanna Foot and Ankle Clinic in July 2015 with right-sided plantar fascial pain accompanied by plantar foot numbness and tingling.  On clinical exam, her foot was neutrally positioned and demonstrated no clinically palpable abnormality. She did have a positive Tinel and Valleix sign. There was mild tenderness along the plantar fascial ligament origin. The patient had been treated by an outside physician for over 5 years with plantar fasciitis.  She had tried various conservative treatment methods including custom orthotics, physical therapy, and a series of corticosteroid injections, all of which provided only temporary relief. She additionally had a history of a prior lumbar laminectomy secondary to pain, after which she began to notice increasing right foot pain and paresthesias.  Her previous spine MRI (June 2014) revealed extramedullary enhancing masses and nerve sheath tumors leading to a diagnosis of neurofibromas.

During her first visit to our clinic in July 2015, an EMG from the previous month was reviewed.  On EMG, there was evidence of tibial neuropathy and degenerative changes of the medial plantar nerve leading to a diagnosis of tarsal tunnel syndrome.  After her first visit, the patient was recommended an additional course of physical therapy, given a script for new custom orthotics, and prescribed a nonsteroidal anti-inflammatory drug, meloxicam (Mobic). Following this course of treatment, the patient’s symptoms did not improve (Figure 1). An MRI was then ordered of the area which revealed a well-encapsulated oval lesion measuring 4.2 x 2.2 x 2.1 cm, appearing hypointense on T1 and hyperintense on T2 consistent with a diagnosis of schwannoma (Figure 2). 

At this point, surgical excision of the mass was recommended to the patient. An oncology referral was discussed, but deferred until after the procedure in the event that surgical pathology findings did not indicate malignancy. She underwent surgical excision of the mass and decompression of the tarsal tunnel in October 2015. 

Figure 1 Preoperative lateral weight bearing radiograph.

Figure 2 Preoperative MRI T1 and T2 images.

The patient was brought into the operating room and placed on the table in a supine position and general anesthesia was administered. Local anesthesia was then administered to the area utilizing a 1:1 mixture of 1% lidocaine plain and 0.5% bupivacaine plain.  A pneumatic calf tourniquet was applied and inflated.  

Attention was then directed to the medial hindfoot, where a curvilinear incision was made just posterior to the medial malleolus and extended to the medial aspect of the glabrous junction at the level of the porta pedis. The incision was then deepened over the tarsal canal. The flexor retinaculum was then identified and released. Extensive tortuous veins were noted within the tarsal tunnel and were gently mobilized. 

Figure 3 Intraoperative image of the soft tissue mass.

 

Figure 4 Intraoperative specimen of the soft tissue mass after removal from tarsal tunnel.

The tibial nerve was then identified and the proximal portion was mobilized. The dissection was then carried distally exposing a large, swollen tibial nerve just proximal to its bifurcation into the medial and lateral plantar nerves.  

A longitudinal incision was then made in the epineurium and the marginal nerve fibers were mobilized  and retracted in an extra capsular fashion. The tumor was then fully exposed. The plane of the tumor capsule was gently dissected from the epineural layers and the tumor was then separated without significant damage to the surrounding nerve fascicles, though there were several small fascicles noted to be entering the tumor at the distal and proximal poles (Figure 3). These fascicles were isolates in an effort to minimize nerve damage, but due to local ingrowth they were impossible to separate from the tumor and were transected.  

Once the tumor was completely removed, the area was thoroughly flushed with sterile saline solution.  The remaining tibial nerve at the level of the lesion was examined and found to demonstrate significant degenerative changes. As there was no obvious tissue to repair, an amniotic graft was then wrapped around the degenerative portion of the nerve in order to promote healing and prevent adhesions.

The incision was then closed in a layered fashion utilizing monocryl suture for the subcutaneous tissues and nylon suture for skin closure. The operative site was then infiltrated with an additional 10 cc of 1:1 mixture of 1% lidocaine plain 0.5% bupivacaine plain.   The incision was then dressed with xeroform and covered with a dry sterile dressing. A modified Jones compression dressing was then applied. The tourniquet was then deflated and a prompt hyperemic response was noted to all digits. 

The pathology report revealed an encapsulated biphasic tumor composed of compact hypercellular areas and mixed hypocellular areas with foci of hyalinization with no malignant features measuring 3.7 x 2.5 x 2.0 cm, consistent with a diagnosis of schwannoma (Figure 4).

The patient was permitted to immediately weight bear postoperatively in a surgical boot. At two weeks postoperative, she underwent suture removal and was transitioned to a street shoe as tolerated. She was followed until one year postoperatively, and found to have no functional limitations, but did continue to notice sensory changes in the plantar foot. 

Discussion

Schwannomas are benign, encapsulated peripheral nerve sheath tumors. They are commonly described throughout the literature by a variety of names: neurilemoma, neuroschwannoma, peripheral glioma, perifibroma, and schwannoma [11,12]. Typically these tumors are found elsewhere in the body (trunk, head, neck, upper extremities) and even more rarely in the lower extremities [2-3, 13].  The foot is noted only to be affected in approximately 10% of cases [3]. There are even fewer noted in the literature to be associated with the tibial nerve and eliciting tarsal tunnel syndromes [5-9].  

Neurofibromas are not typically found in with the foot and ankle.  In a study by Bakotic and Borkowski of primary soft tissue neoplasms of the foot, schwannomas and neurofibromas were noted to account for only 5.4% and 2.7% of all benign soft tissue tumors, and 2.0% and 1.0% of all total neoplasms respectively in the foot and ankle [14].  It is rarely reported to find these two types of tumors in association with one another, with only one report of a schwannoma associated with a neurofibroma in the tarsal tunnel [10]. 

There are currently no other reports of a patient with a schwannoma eliciting secondary tarsal tunnel syndrome and a history of spinal neurofibromas. Currently the recommended treatment for schwannomas of the foot and ankle is open surgical resection [15]. Fortunately, surgical resection has positive results with minimal morbidity and recurrence if resected entirely [16,17]. It is recommended to remove the lesion in total with great care not to damage the nerve through excessive violation of the nerve sheath or compromising the marginal neural fibers. 

We report a case of successful excision of a schwannoma of the tibial nerve located within the tarsal tunnel, eliciting symptoms leading to a diagnosis of tarsal tunnel secondary to tumor. The patient did have a significant medical history of painful neurofibromas of the lumbar spine confirmed on MRI with a subsequent lumbar laminectomy. While the patient did have EMG findings positive for tibial neuropathy and degeneration of the medial plantar nerve, we cannot effectively determine whether the patient’s symptoms were solely related to compression from the longstanding mass within the tarsal tunnel or if they were possibly exacerbated by the patient’s history of lumbar neurofibromas with subsequent surgical intervention. 

The patient’s postoperative course was uneventful.  She did regain some hindfoot and midfoot sensation, while completely eliminating her preoperative pain.  However, parasthesias persisted within the forefoot. 

References

  1. Graviet S, Sinclair G, Kajani N. Ancient schwannoma of the foot. J Foot Ankle Surg. 1995;34(1):46-50.
  2. Ackerman LV, Taylor FH. Neurogenous tumors within the thorax; a clinicopathological evaluation of forty-eight cases. Cancer. 1951;4(4):669-91.
  3. Odom RD, Overbeek TD, Murdoch DP, Hosch JC. Neurilemoma of the medial plantar nerve: a case report and literature review. J Foot Ankle Surg. 2001;40(2):105-9.
  4. Weiss S, Goldblum J, Folpe AL. Schwannoma. In: Enzinger and Weiss’s Soft Tissue Tumors, ed 5, Elsevier Mosby, Maryland Heights MO, 2008, pp. 853-862
  5. Hallahan K, Vinokur J, Demski S, Faulkner-jones B, Giurini J. Tarsal tunnel syndrome secondary to schwannoma of the posterior tibial nerve. J Foot Ankle Surg. 2014;53(1):79-82.
  6. Grossman MR, Mandracchia VJ, Urbas WM, Mandracchia DM. Neurilemmoma of the posterior tibial nerve with an uncommon case presentation. J Foot Surg. 1992;31(3):219-24.
  7. Mangrulkar VH, Brunetti VA, Gould ES, Howell N. Unusually large pedal schwannoma. J Foot Ankle Surg. 2007;46(5):398-402.
  8. Judd T, Jones T, Thornberry L. Schwannoma of the posterior tibial nerve: case study. J Am Podiatr Med Assoc. 2014;104(5):539-43.
  9. Nawabi DH, Sinisi M. Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis. J Bone Joint Surg Br. 2007;89(6):814-6.
  10. Tladi MJ, Saragas NP, Ferrao PN, Strydom A. Schwannoma and neurofibroma of the posterior tibial nerve presenting as tarsal tunnel syndrome: review of the literature with two case reports. Foot (Edinb). 2017;32:22-26.
  11. White NB. Neurilemomas of the extremities. J Bone Joint Surg Am 49:1605-1610, 1967.
  12. Spiegel PV, Cullivan T, Reiman HM. Neurilemoma of the lower extremity. Foot Ankle 6:194-8, 1986.
  13. Jacobson JM, Felder JM, Pedroso F, Steinberg JS. Plexiform schwannoma of the foot: a review of the literature and case report. J Foot Ankle Surg. 2011;50(1):68-73.
  14. Bakotic BW, Borkowski P. Primary soft-tissue neoplasms of the foot: the clinicopathologic features of 401 cases. J Foot Ankle Surg. 2001;40(1):28-35.
  15. Kellner CP, Sussman E, Bar-david T, Winfree CJ. Schwannomas of the foot and ankle: a technical report. J Foot Ankle Surg. 2014;53(4):505-10.
  16. Carvajal JA, Cuartas E, Qadir R, Levi AD, Temple HT. Peripheral nerve sheath tumors of the foot and ankle. Foot Ankle Int. 2011;32(2):163-7.
  17. Kim DH, Ryu S, Tiel RL, Kline DG. Surgical management and results of 135 tibial nerve lesions at the Louisiana State University Health Sciences Center. Neurosurgery. 2003;53(5):1114-24.

Surgical treatment of a large plexiform neurofibroma of the lower extremity

by Jacob Jensen1, David Shofler2*, Della Bennett3

The Foot and Ankle Online Journal 10 (3): 5

Plexiform neurofibromas are benign nerve tumors occurring in approximately 30% of patients with neurofibromatosis type 1. They develop as neural proliferations of single or multiple nerve fascicles, and are typically highly vascular in nature. In this case report, we describe a 28-year-old male with a paternal family history of neurofibromatosis type 1 and a large plexiform neurofibroma of his left lower extremity present. Following consultation and shared decision-making, the patient underwent surgical debulking primarily to reduce pain, to improve shoe gear fit, and to improve ambulation.  

Keywords: plexiform neurofibromas, neurofibromatosis, surgery

ISSN 1941-6806
doi: 10.3827/faoj.2017.1003.0005

1 – PGY2, Chino Valley Medical Center, Chino, CA
2 – Assistant Professor, Western University of Health Sciences
3 – Gemini Plastic Surgery
* – Corresponding author: dshofler@westernu.edu


A 28-year-old male with a past medical history of neurofibromatosis type 1 was seen for evaluation and management of a painful mass on his lateral left leg (Figure 1). He was no longer able to wear normal shoes, which in turn affected his activities of daily living. His surgical history included a prior debulking procedure of his left medial leg and foot at the age of 3. His social history included active tobacco use of a ½ pack of cigarettes a day, and had not graduated from high school. The patient related an extensive paternal family history of neurofibromatosis type 1, affecting multiple family members.  He reported a paternal family member passing away from a peritoneal malignancy caused by plexiform transformation into a malignant peripheral nerve sheath tumor.

Figure 1 Preoperative weightbearing and nonweightbearing clinical appearance of the left lower extremity, depicting the large mass.

Preoperative surgical planning included a coordinated effort between podiatric and plastic surgeries.  Surgical and conservative options were discussed in detail with the patient. The elected plan for the surgery was to debulk the lateral leg mass, with the goal of reducing the associated pain and to allow the patient to fit into a shoe. Risks and benefits were discussed in detail with the patient, and the patient was educated regarding the likelihood and speed of mass regrowth.  

Results

The patient underwent surgical debulking as an outpatient. Preoperatively, blood was typed and crossed in anticipation of blood loss secondary to the highly vascular nature of plexiform neurofibromas. A thigh tourniquet was used, and the patient was placed into a lateral decubitus position. A large semi-elliptical incision was utilized, oriented in line with the mass. The mass was identified and carefully dissected, with electrocautery used as necessary. The mass was noted to readily extend through tissue planes, and was not sharply defined. Local neurovascular structures were carefully avoided during dissection of the mass. With direct and unobstructed exposure obtained, the large mass was debulked with representative samples sent to pathology. The mass was noted to extend into the peroneal tendons, lateral ankle ligaments, and the fat pad of the heel; these anatomic structures were carefully preserved during the debulking process.

Following debulking of the mass, the tourniquet was released. Electrocautery was again employed to assist in obtaining hemostasis. Epinephrine soaked gauze was also employed as a hemostatic agent to promote vasoconstriction, further reducing blood loss during dissection. The surgical site was closed in layers, with Floseal hemostatic matrix (Baxter International, Deerfield, Illinois) applied during closure. A passive, closed, surgical drain was inserted prior to skin closure (Figures 2 and 3).

Figure 2 Immediate postoperative image of the left lower extremity following surgical debulking, with the surgical drain visible.

Figure 3 Postoperative image of the left lower extremity at the first postoperative visit, with surgical drain visible.

Discussion

Neurofibromatosis type I (NF-1), formerly known as Recklinghausen’s or von Recklinghausen disease, is a subtype of neurofibromatosis accounting for 90% of cases [1]. NF-1 is an inherited, autosomal dominant, single-gene disorder of chromosome 17: this non-sense mutation takes place on the NF-1 gene, with a prevalence of 1/3000 births and an equal distribution between males and females [2]. NF-1 usually presents in childhood, and manifestations include café au lait spots, neurofibromas, skeletal dysplasia, and neuropathy secondary to space-occupying neurofibromas [3,4].

Plexiform neurofibromas occur in approximately 30% of the patients with neurofibromatosis type I [5]. Malignant transformation occurs in about 2-16% of cases and is diagnosed with histopathologic biopsy [4,6]. Treatment planning requires consideration of the patient’s goals of treatment, the extent of the deformity, and the presence of malignant transformation.

It is of vital importance to plan preoperatively in order to anticipate the atypical surgical dissection. Surgical time may be longer than anticipated, as anatomic layers will be obscured and violated by the invasive and vascular nature of these masses. Preoperatively, blood should be typed and crossed with the anticipation of significant levels of blood loss. Careful, layered closure should be performed, with the incorporation of hemostatic agents. A closed surgical drain should be considered as well.

Due to the invasive and diffuse invagination of the mass, multiple tissue planes were carefully dissected with the anticipation of overall “debulking” rather that complete marginal resection of the soft tissue mass.

Though rarely encountered, management of large plexiform neurofibromas should include a shared-decision making process and a realistic depiction of the surgical outcome. Operative management should be deferential to the highly vascular and invasive nature of these soft tissue tumors.

References

  1. Ghalayani P1, Saberi Z, Sardari F. Neurofibromatosis type I (von Recklinghausen’s disease): A family case report and literature review. Dent Res J (Isfahan). 2012 Jul;9(4):483-8.
  2. Evans DG, Howard E, Giblin C, et al. Birth incidence and prevalence of tumor-prone syndromes: estimates from a UK family genetic register service. Am J Med Genet A. 2010;152A:327–332. 

  3. Hillier JC, Moskovic E. The soft tissue manifestations of neurofibromatosis type 1. Clin Radiol. 2005;60:960–7.
  4. Neurofibromatosis Fact Sheet NINDS, May 2011. NIH Publication No. 11-2126.
  5. Huson SM, Hughes RA. London: Chapman and Hall Medical; 1994. The Neurofibromatosis: A Pathogenetic and Clinical Overview.
  6. Sabatini C, Milani D, Menni F, et al. Treatment of neurofibromatosis type 1. Curr Treat Options Neurol. 2015;17:355. 


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Neurofibroma of the Anterior Leg: A Case Report

by Brian Carpenter, DPM, FACFAS1 , Nathan Stickney, DPM2

The Foot and Ankle Online Journal 5 (6): 2

A neurofibroma is a benign nerve sheath tumor usually involved with the peripheral nervous system. Neurofibromas are commonly associated with neurofibromatosis type 1, including being an inclusion criteria, but are not always associated with the disease. Neurofibromas are uncommon in the foot and ankle and account for less than 10% of all soft tissue tumors of the foot and ankle. (1) Peripheral nerve tumors are most common in the face, neck, and flexor surfaces. Neurofibromas are characterized by a combination of cells of the nerve sheath including: Schwann cells, peri-neurial cells, and fibroblasts. (2) We report a rare case of a neurofibroma present in the anterior leg arising secondary to a traumatic event.

Key Words: Neurofibroma, Schwann cells, neurofibromatosis, peripheral nervous system

Accepted: May, 2012
Published: June, 2012

ISSN 1941-6806
doi: 10.3827/faoj.2012.0506.0001


Neurofibromas are among the most common and debilitating complications of neurofibromatosis type 1 (NF1). They account for substantial morbidity, including disfigurement, functional impairment, and may even be life threatening. Plexiform neurofibromas are also subject to transformation into malignant peripheral nerve sheath tumor. The current mainstay of treatment of plexiform neurofibromas, and of malignant peripheral nerve sheath tumors is surgical resection [7].

Neurofibromas arise from a combination of neural cells including Schwann cells, peri-neurial cells, and fibroblasts. Neurofibromas often present painless but can cause debilitating pain and motor sensory dysfunction.

Neurofibromatosis I, also known as “von Recklinghausen disease,” is an autosomal dominant condition which is clinically characterized in part by pigmented skin lesions known as café-au-lait spots, benign cutaneous and subcutaneous tumors known as neurofibromas, distinctive bone lesions, and focal malformations of the iris. It is the most common single gene disorder in humans and results from the defective protein neurofibromin, which is thought to act as a tumor suppressor [6]. Neurofibromas are most commonly associated with NF1.

Case Report

A 38 year-old female presented with extreme pain over her anterior leg secondary to a traumatic event. She stated she had a motor vehicle accident five years ago in which her anterior leg was thrown against the front dash and resulted in a twisting motion, as she was turned backwards in the seat after the crash. She was then seen by an outside physician for this pain. The physician surgically removed the nerve in this area and buried the ends in the muscle belly. This gave her relief for approximately four to six months. The pain then resumed in the same area as a burning, aching type pain. She then saw a different physician who started her on phenol injections in the affected area. She relates these injections helped for six months and then stopped relieving any pain. She states she is now noticing skin color changes over the area of these injections. She presented with loss of sensation over the anterior area extending distal to digits two through four. On physical exam she had extreme pain on palpation over the previous incision site. The skin integrity at this site notes discoloration and dystrophic. A soft tissue mass was noted in this area of the anterior leg. Muscle strength and vascular status were intact.

Magnetic resonance imaging demonstrated a linear nodular intermediate signal in T1and hyperintense on T2. The nodule showed hypointense to fat on T2 fast spin-echo measuring 6 mm. Linear signal alteration extends to the deep fascia and shows a subtle nodular region in the subcutaneous region. (Figs. 1A and 1B) The osseous structures were unremarkable and there were no signs of malignancy noted. Electromyography results demonstrated an abnormal finding in an accessory peroneal nerve branch directly in the area of discomfort.

 

Figures 1A and 1B Magnetic resonance image (MRI) showing a hyperintense signal at the surface marker 7 cm proximal to the ankle mortise. There is also a perifascial hyperintensity superficial to the anterior musculature with a nodular like signal anterior to this finding. (A) MR image showing a hyperintense, linear signal extending into the deep fascia. Faint nodularity is noted on the lesion which measures 6 mm. (B)

Surgical excision was performed on the mass of the anterior leg. There were large areas of thick scar tissue experienced in dissection through the previous incision. The mass had a noted small nerve branch running superior and medial to it. A 0.6 x 0.6 x 0.5 mass was dissected from the nerve branch and removed.

The small nerve branch was then dissected 3 cm proximal where an incision was made in the anterior muscle belly. The nerve was placed through this incision a full centimeter and sewn into place in the muscle belly. Pathologic evaluation showed a fibroma with nerve tissue involvement. An S-100 stain was then performed on the tissue revealing the nodule to be composed of bundles of cells with spindled nuclei. (Fig. 2) The nuclei are bland and there are mitoses present. The overall cellularity of the lesion was low with dense collagen bundles noted. S-100 stain illustrates that some but not all of the cells in the lesion expressed the antigen. Often only a subset of cells stains with the antigen, in keeping with the observation that neurofibromas contain a mixed population of cells. Due to neuron involvement the pathologist gave the diagnosis of neurofibroma.

Figure 2 T-100 which stains neurons among other things, shows patchy positive staining within the mass. The positive staining is seen in small nerve fibers embedded in the lesion.

At 5 month follow up there is no pain on palpation to the anterior leg. She has had no reoccurrence of the symptoms. She has gone back to work as a flight attendant completely pain free. The incision site healed with no complications.

Discussion

Neurofibromas are tumors involving the fascicles of elongated neuron cells. Although rare in the foot and ankle they can be present especially in the flexor surfaces. Usually associated with neurofibromatosis these tumors can present in patients without the disease. Neurofibromatosis is a genetic disorder of chromosomal mutation in neural crest cells. Neurofibromas may be benign cutaneous nodules and painless but can also cause serious problems compressing nerves and other tissues. A history of trauma can incite a previously painless neurofibroma. Neurofibromas can undergo malignant transformation into a malignant peripheral nerve sheath tumor. In some reports the incident rate has been up to 2-5% [1]. Only two forms of neurofibroma, plexiform and localized intraneural neurofibroma, are significant precursors of malignant peripheral nerve sheath tumors [5].

A series by Donner performed a study of 263 patients who underwent removal of neural sheath tumors. Of these patients, 85% had partial or complete resolution of pain and 87% had improved or no changes in motor sensory function [3]. Nagel reported a case of an athletic long distance runner who developed peroneal neuropathy which did not improve with rest. After further workup he found a mass in the common peroneal nerve causing this foot drop. Upon removal the mass was confirmed to be a neurofibroma. The patient’s symptoms improved once the mass was removed [4].

Certainly neurofibromas can be a harmful soft tissue mass in the body. Although neurofibromas are benign they do have a small incidence to transform into malignancy in the body. Neurofibromas can also cause crippling pain and affect the body’s function. Early diagnosis can help prevent nerve damage or deformity.

References

1. Blitz N, Hutchinson B, Grabowski M. Pedal plexiform neurofibroma: Review of the literature and case Report. J Foot Ankle Surg 2002 41(2):117-124.  [PubMed]
2. Mendeszoon M, Cunningham N, Crockett R, Kushner D. Schwannoma: A case report. Foot and Ankle Online J 2009: 2 (10): 4 [Website]
3. Donner TR, Voorhies R, Kline D. Neural sheath tumors of major nerves. J Neurosurgery 1994 81:362-373.  [PubMed]
4. Nagel A, Greenebaum E, Singson R, Rosenwasser M, McCann P. Foot drop in a long distance runner. An unusual presentation of neurofibromatosis. Orthop Rev 1994 23: 526-530. [PubMed]
5. Woodruff J. Pathology of tumors of the peripheral nerve sheath in type 1 neurofibromatosis. Am J Med Genet 1999 89: 23-30. [PubMed]
6. Geller D, Gebhardt M. Malignant peripheral nerve sheath tumor. Liddy Shriver Sarcoma Initiative Online. [Webpage]
7. Korf B. Plexiform neurofibromas. Am J Med Genet 1999 89: 31-37. [PubMed]
8. Carvajal  J, Cuartas E, Qadir R, Levi A, Temple T. Peripheral nerve sheath tumors of the foot and ankle. Foot Ankle Int 2011 32: 163-167. [PubMed]
9. Meek R, Sharma H, Jane M, Raby N, Macduff E, Reid R. Solitary intraosseous schwannoma of the metatarsal bone: case report. Foot Ankle Int 2007 28: 845-848. [PubMed]
10. Jacobsen J, Felder J, Pedroso F, Steinberg J. Plexiform schwannoma of the foot: A review of the literature and case report. J Foot Ankle Surg 2011 50: 68-73. [PubMed]


Address correspondence to: Nathan Stickney DPM email: nstickne@jpshealth.org

1Brian Carpenter, DPM, Associate Professor University of North Texas Health Science Center, Department of Orthopaedics. Director of Podiatric Medical Education John Peter Smith Hospital, Ft Worth, TX.
2Nathan Stickney, DPM PCY-2 John Peter Smith Hospital Podiatric Residency Program, Ft Worth, TX.

© The Foot and Ankle Online Journal, 2012