A 49-year-old female with a complicated past medical history reports to her family doctor that she has been experiencing vague pain in the upper left neck under the angle of her jaw with a sensation that there is something to clear from her throat but she is unable to. This had been occurring while jogging and these symptoms first began in May, 2007. At one point she described this to her family doctor as being almost like a toothache. Among other things, this patient was also under the care of a pain management unit for chronic pain and the family doctor presumed this could represent atypical facial pain in line with a temporomandibular disorder. Concurrently, because of unrelated complaints earlier of shortness of breath, she had undergone recent pulmonary function tests, which were normal. Ongoing complaints of shortness of breath following normal pulmonary function tests prompted the physician to order a CT scan to survey the patient’s neck to rule out upper airway constriction. This CT was completed on Oct 23rd, 2007 (Fig. 1). The radiologist who reported the CT identified a mass in the area of the inferior alveolar nerve and suggested a referral to the Oral and Maxillofacial Surgery service. He also reported that from the neck CT, no abnormality was identified that could account for the patient’s dyspnea. He further recommended MR imaging to further detail this soft tissue lesion.
This woman was then seen by the OMF service and assessed on Dec. 20, 2007. Her presenting chief complaint and history of chief complaint were as outlined above. The patient had a long and complicated past medical history including chronic low back and neck pain attributed to two past motor vehicle collisions in 1990 and 1995. An episode of myocarditis in the past, which led to a two-month ICU stay was complicated by the development of reflex sympathetic dystrophy of her left leg following a per-cutaneous cardiac intervention. During that admission she also suffered an episode of acute renal failure that has left her with some reported mild chronic renal failure. Other past medical history includes osteoporosis (for which she receives an IV bisphosphonate every three months), irritable bowel syndrome, gastro-esophageal reflux disease, allergic rhinitis, asthma, and migraine headaches. As mentioned, she was actively being followed by the chronic pain management service.
Medications included pamidronate IV every three months, nasonex 50 g spray each nostril once daily, tramacet 37.5/325 mg 1-2 tabs every six hours as needed, medical marijuana 2.5g three times weekly, Ca 1500 mg daily, Vit D 1000 IU daily. Reported allergies noted were to MAOIs, heparin, talwin, penicillin, morphine, codeine, theophylline, methadone, lactose, as well as other environmental and chemical sensitivities. Previous surgeries included hysterectomy, cholecystectomy, acromioplasty, tonsils and adenoids.
Physical examination on the day of presentation (Dec. 20, ’07) revealed a normal head and neck hard and soft tissue examination with no cranial nerve abnormalities including symmetrical normal intact sensation in the left mental nerve distribution. Cervical examination revealed no adenopathy or masses. Intraoral examination also was unremarkable and the mass in question was not palpable.
Based on the results of the aforementioned CT examination and discussion with the patient a decision was made to complete an MRI to further delineate the lesion and to biopsy the lesion for diagnosis. An MRI on Dec 27, 2007 (Fig. 2) confirmed a mass in the pterygomandibular space. These findings were found to be consistent with previous CT findings of a 2.3 cm x 2.4 cm x 2.5 cm mass. The lesion was described as laminated with a high density connective tissue ring with increased T1 signal from likely increased Ca++ uptake in the capsule. The body of the lesion showed increased T2 signal. The lesion showed some extension into the mandibular canal with no extension superiorly into foramen ovale. There was no identifiable invasion of the pterygoid musculature. The lesion was large however and not far from the great vessels. No cervical adenopathy was identified. The radiologist’s impression was consistent with Schwannoma.
On Jan 8th 2008, the patient underwent an incisional biopsy in the OR.
On Jan. 29, 2008, a diagnosis of Neurofibroma was confirmed histopathologically. The biopsy contained nerve fascicles with myxoid matrix and S100 positive spindle cells consistent with Schwann cells. Neurofilament stain showed axons and myxoid Schwann cell proliferation. CD34 stain was also diffusely positive. Diagnosis was consistent with a neurofibroma but would include a traumatic neuroma.
A lengthy discussion took place with the patient regarding how best to manage this lesion.
On September 5, 2008, the patient underwent a mandibular swing dissection for access to the oropharynx (Figs. 3 & 4). The access afforded by this technique is nicely reviewed in the paper by Stewart and Bailey1 who dealt with a lesion in a very similar location. The inferior alveolar nerve was found to be lying on the surface of the tumour and the mass was removed with a nerve sparing procedure. Her course in hospital was uneventful. She had a short stay in recovery and was transferred to the ward where she convalesced well. She was discharged home on post-operative day two.
Be cause of it’s benign nature it was not life threatening and excising it would certainly pose surgical challenges. An earlier article illustrates the challenges in dealing with an inferior alveolar nerve neurofibroma in this location. 1 The unknowns were how long had it been present and what was its rate of growth? A mutual decision was made at this time to monitor it for a period of 6-9 months and reevaluate with follow up MRIs for changes.
On June 12, 2008, after five months, the patient returned complaining of increased symptoms. She continued to have tightness and globus sensation in the pharynx however now she was complaining of shooting pains in her left chin, cheek and tongue. She was also describing an increase in otalgia and headache. A repeat MRI was then performed which showed no significant changes in dimensions of the original lesion with no new extension and again no identifiably positive nodes. After discussing the results with the patient, a decision was made to remove the lesion and she was planned for the OR. Preoperative blood work revealed a normal CBC, electrolytes, TSH, INR, PTT. Her preoperative creatinine was 81 mmol/l. She also underwent blood typing and was screened for antibodies.
Final pathology was available about two weeks postoperatively (Fig. 5). Histological examination showed fusiform expansion of the nerve with central residual nerve tissue surrounded by a proliferation of spindle cells with a collagenous stroma. The density of collagen was highly variable, ranging from areas with thick dense colla- gen bundles to areas with accumulation of pale blue-grey stromal mucin. Immunohistochemical stains demonstrated large numbers of S100-positive Schwann cells as well as CD34-positive fibroblasts. Epithelial membrane antigen (for perineurial cells) was completely negative, except for a compressed layer surrounding the tumour, consistent with the preexisting epineurium. Scattered residual axons were demonstrated throughout the tumour using a neurofilament immunostain. Scattered mast cells were also noted, as were multiple aggregates of small lymphocytes, mostly CD3-positive T cells. The etiology of the latter is unclear, and it raised the possibility of an inflammatory process (localized hypertrophic neuropathy [LHN], pseudotumoral hypertrophic neuritis). The lack of “onion-bulb” whorls characteristic of LHN and the rarity of that condition in this location argued against that diagnosis. Overall, the mass was considered
to represent a localized (intraneural) neurofibroma. There was no significant atypia, mitotic activity or necrosis to suggest a malignant peripheral ner
ve sheath tumor.
Review of the Literature
Neurofibromas can occur in isolation or as a component of Neurofibromatosis — also known as von Recklinghausen’s Disease of the Skin. 2,3 When seen as an isolated lesion it is less commonly found intraorally but can occur in the tongue or buccal mucosa as the more common sites. The oral
and maxillofacial surgery literature has several case reports although this is not a common tumour of the jaws or mouth. 4-14 There are several known variants of Neurofibromatosis and a set of criteria is required to be diagnostic of the most common variant Type 1.2,3
Solitary neurofibromas account for 90% of all neurofibroma cases. Otherwise they are found in association with Neurofibromatosis (NF) Type 1 or 2. Type 1 is the more common of the two syndromes where the neurofibromas are located peripherally, whereas in Type 2 they are found centrally. The other possible findings of NF Type 1 include caf au lait pigmentation, multiple neurofbromas, iris hamartomas, distinct and varied osseous changes of any bone and an affected first degree relative (autosomal dominant inheritance in 50% of cases).15 None of these applied to this case.
As early as 1969, Eversole wrote a good review that discusses neurofibroma in context with other neural tumours, both benign and malignant. 3 Neurofibromas usually present clinically intimate with the nerve from which they have arisen. Most times it is not possible to separate the two and they are unencapsulated, making their removal more difficult — usually requiring a surgical margin to ensure complete resection. Fortunately the malignant counterpart, the neurofibrosarcoma, is rare, although there are case reports associated with the trigeminal nerve15,16 and obviously would require different management. Although rare, this could not be ruled out definitively until histologic examination of the excised specimen was done.
Follow Up
On Sept 11, 2008, the patient was seen in clinic for suture removal on post operative day six (Fig. 6). At that time she did report cutaneous paresthesia in the distribution of the left mental nerve. At one month postoperatively she was found to be doing well. Her occlusion was restored to normal. She had no ongoing dysphagia and the symptoms that were identified as her chief complaint were relieved. At six months postoperatively she continued to improve. Her occlusion was stable and she was having some return of sensation to the mental nerve distribution. Her scar (Fig. 7) is maturing and there is no facial nerve dysfunction. There is a plan for a follow up MRI in one year and the patient will be followed indefinitely.
Discussion
As dental practitioners we need to remind ourselves that all organic soft tissue disease exists within the oral and maxillofacial complex where we work every day. Atypical facial pain is common and we deal with it all the time. It is very easy on occasion to jump to a treatment plan such as bite plane therapy or other conservative management based on a set of symptoms and complaints. We need to be vigilant with our history and physical assessment with these patients in particular. Although the vast majority of atypical facial pain is a temporomandibular disorder or variant thereof, the occasional person presents with a tumour or other substantial pathologic lesion. We do not want to miss any of these in our initial workup.
Archie Morrison, DDS, MS, FRCD(C) is Associate Professor Dalhousie University and Active Staff OMF Surgery QE II Health Sciences Centre Halifax, NS.
Graham Cobb, BSc, DDS is Resident OMF Surgery Dalhousie University and QE II Health Sciences Centre Halifax, NS.
Martin Bullock, MD, FRCP(C) is Active Staff Department of Anatomic Pathology Dalhousie University and QE II Health Sciences Centre Halifax, NS.
Oral Health welcomes this original article.
References
1. Stewart, A and Bailey, BMW. Neurofibroma of the inferior alveolar nerve: diagnostic and management difficulties. Br J Oral Maxillofac Surg. 1992; 30: 56-58.
2. Marx, Robert E and Stern, Diane. Oral and Maxillofacial Pathology -A Rationale for Diagnosis and Treatment. Quintessence Publishing Company, 2003.
3. Neville, Brad. Oral and Maxillofacial Pathology, 2nd edition. WB Saunders Publishers, 2002.
4. Apostolidis, C, Anterriotis, D, Rapidis, A and Angelopoulos, A. Solitary intraosseous neurofibroma of the inferior alveolar nerve: a case report. J Oral Maxillofac Surg. 2001; 59: 232-235.
5. Bruce, KW. A neurofibroma of the oral cavity. Oral Surg Oral Med & Oral Path. 1954; 7: 1150.
6. Goldman, HM. Case reports from the files of the Registry of Dental and Oral Pathology; Neurofibroma. Am J Orthodontics and Oral Surg. 1944; 30: 289-295.
7. Larsen, A, Praetorius, F and Hjorting-Hansen, E. Intraosseous neurofibroma of the jaws. Int J Oral Surg 1978; 7: 494-499.
8. Muller, H and Slootweg, PJ. Maxillofacial deformities in neurofibromatosis J Maxillofac Surg. 1981; 9(2):89-95.
9. Polak, M, Polak, G, Brocheriou, C and Vigneul, J. Solitary neurofibroma of the mandible: case report and review of the literature. J Oral Maxillofac Surg. 1989; 47: 65-68.
10. Schroff, J. Solitary neurofibroma of oral cavity. J Am Dent Assoc. 1945; 32: 199.
11. Sharawy, A and Springer, J. Central neurofibroma occurring in the mandible. Oral Surg Oral Med & Oral Path. 1968; 25(6): 817-821.
12. Ueda, M, Suzuki, H and Kaneda, T. Solitary intraosseous neurofibroma of the mandible: report of a case. Nagoya J Med Sci. 1993; 55: 97-101.
13. Zilkens, K. Ube rein neurinom am unterkiefer. Ztschr Stomatol. 1937; 35: 461.
14. Eversole, LR. Central benign and malignant neural neoplasms of the jaws: a review. J Oral Surgery 1969; 27: 716-721.
15. Liwnicz, BH. Bilateral trigeminal neurofibrosarcoma. J Neurosurg 1979; 50: 253-256.
16. Upton, LG, Hayward JR and Kerr, DA. Neurofibrosarcoma of the mandible. J Oral Surgery. 1977; 35: 504-506.
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This patient was also under the care of a pain management unit for chronic pain and the family doctor presumed this could represent atypical facial pain in line with a temporomandibular disorder
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The lesion showed some extension into the mandibular canal with no extension superiorly into foramen ovale
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Histological examination showed fusiform expansion of the nerve with central residual nerve tissue surrounded by a proliferation of spindle cells with a collagenous stroma
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There was no significant atypia, mitotic activity or necrosis to suggest a malignant peripheral nerve sheath tumor
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As dental practitioners we need to remind ourselves that all organic soft tissue disease exists within the oral and maxillofacial complex where we work every day
