|Year : 2016 | Volume
| Issue : 2 | Page : 95-97
Solitary extraosseous neurofibroma of hard palate: Report of a case with a review of literature
Madhu Priya, Satvinder Singh Bakshi, V Nirmal Coumare, S Vijayasundaram, Muhammed Nabeel Latheef
Department of ENT and Head and Neck Surgery, Mahatma Gandhi Medical College and Research Institute, Puducherry, India
|Date of Web Publication||25-Oct-2016|
Satvinder Singh Bakshi
House Number B2, Shree Pushpa Complex, 15th Bharathi Street, Ananda Nagar, Puducherry - 607 402
Source of Support: None, Conflict of Interest: None
Neurofibromas (NFs) are benign tumors arising from peripheral nerves. Although common in other head and neck sites, they have rarely been reported in the oral cavity. A 55-year-old male presented with a slowly progressive swelling in the hard palate, which was completely excised. Histopathological examination revealed a NF, which was confirmed by immunohistochemical staining for S-100. The differential diagnosis of NF should be kept in mind while evaluating a swelling arising from the hard palate. The clinical features, types, diagnosis, pathology, and treatment of NF are discussed.
Keywords: Hard palate, oral cavity tumor, solitary neurofibroma
|How to cite this article:|
Priya M, Bakshi SS, Coumare V N, Vijayasundaram S, Latheef MN. Solitary extraosseous neurofibroma of hard palate: Report of a case with a review of literature. J Dent Allied Sci 2016;5:95-7
|How to cite this URL:|
Priya M, Bakshi SS, Coumare V N, Vijayasundaram S, Latheef MN. Solitary extraosseous neurofibroma of hard palate: Report of a case with a review of literature. J Dent Allied Sci [serial online] 2016 [cited 2020 Sep 18];5:95-7. Available from: http://www.jdas.in/text.asp?2016/5/2/95/192971
| Introduction|| |
Neurofibroma (NF) is a benign neural tumor which originates from the peripheral nerve sheath and it is composed of a variable mixture of Schwann cells, perineurial-like cells, and fibroblasts. NF may occur as a solitary lesion or as part of a generalized syndrome known as Von Recklinghausen's disease. Solitary type rarely involves the head and neck and even in the head and neck region, the oral cavity is seldom involved with few isolated case reports of the tumor occurrence in the buccal mucosa, floor of mouth, lips, and gingiva. Complete surgical excision is the treatment of choice and the prognosis is good. We report a rare case of solitary NF of the palate and review the current literature on this interesting pathology.
| Case Report|| |
A 55-year-old male presented with the complaints of a painless, progressive swelling in the oral cavity for 2 years. Examination revealed a single, firm, nontender, 2 cm × 2 cm, sessile swelling in the hard palate more toward the left side crossing the midline [Figure 1]. The mucosa over the swelling was intact and nonulcerated. Computed tomography (CT) scan showed a nonenhancing soft tissue lesion with no bony defect in the hard palate. A provisional clinical diagnosis of the benign neoplasm of minor salivary gland was made and surgical excision of the mass was planned.
|Figure 1: Patient with a 2 cm × 2 cm smooth mass arising from the hard palate on the left side|
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The palatal mass was excised in toto and the tissue was sent for histopathological examination. The final histopathological diagnosis was reported as NF of the palate, and microscopy revealed tumor composed of bundles and interlacing thin fascicles of spindle-shaped cells with ovoid to elongated, fine homogeneous to dark staining bland nuclei, inconspicuous nucleoli, occasional pseudoinclusions, and eosinophilic cytoplasm with indistinct cell borders, set in an edematous to collagenized stroma with interspread small caliber blood vessels, mild infiltrates of lymphocytes, and occasional plasma cells [Figure 2]. The slide was sent for immunohistochemistry, which was positive for S-100 protein [Figure 3].
|Figure 2: Histopathological picture showing tumor composed of bundles and interlacing thin fascicles of spindle-shaped cells with ovoid to elongated, fine homogeneous to dark staining bland nuclei, and eosinophilic cytoplasm, with indistinct cell borders and mild infiltrates of lymphocytes and occasional plasma cells (H and E, ×400)|
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|Figure 3: Immunohistochemistry slide showing tumor cells diffusely and strongly positive for S-100 (IHC, ×100)|
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The patient was re-evaluated, and a thorough dermatological and ophthalmic examination was carried out to look for any evidence of associated NF-I. Absence of systemic involvement and negative family history confirmed it as a solitary case of NF of the hard palate. The patient was asymptomatic and was on follow–up for 5 months with no evidence of recurrence. He had no residual neurological defect.
| Discussion|| |
NF is a benign tumor of the peripheral nerve sheath. Reccardi  described at least seven types of NF; however, only two distinct forms are widely accepted, namely a peripheral form known as neurofibromatosis type I (NF-I) and a central form known as NF-II.
NF-I was first described by Recklinghausen in 1882, it is the classical form and presents as a part of von Recklinghausen's disease of the skin. It accounts for 90% of all cases of neurofibromatosis. The diagnostic features of NF-I include multiple NFs on the body, cutaneous café au lait macules, and lisch nodules (pigmented iris hamartomas). NF-II has a much lower prevalence and it is usually characterized by the presence of bilateral acoustic neuromas; it may also be associated with multiple endocrine neoplasia III.
Among the neural lesions affecting the head and neck, NFs are relatively common,, with the reported incidence in the head and neck being 37%. The head and neck is commonly involved because of rich innervations of this area. NFs of the oral cavity and oropharynx are extremely rare, ranging from 2% to 7%, and are mostly associated with NF-I. In the oral cavity, the tumor often involves the trigeminal and upper cervical nerves, with the most common site in the oral cavity being the tongue followed by buccal mucosa, the floor of mouth, lips, and gingiva. Solitary NF is a rare variant of NF; it seldom affects the head and neck. They are distinct as unlike other NFs, they lack the systemic and hereditary components. We searched the English literature for similar cases and found only three cases of solitary extraosseous NF in the hard palate.,, This is probably the fourth case.
No racial or gender predilection has been described for oral NF; however, Cherrick and Eversole  observed a predilection for females. NF can present at any age  ranging from 10 months to 70 years with an average of 45 years.
The exact cause for solitary NF is unknown. It has been proposed that solitary NF is a hyperplastic hamartomatous malformation rather than a neoplastic disease. They are thought to originate from Schwann cells, perineural cells, and fibroblasts.
The oral lesions usually present as a slowly progressive painless discrete swelling which are either sessile or pedunculated with nonulcerated mucosa. The mucosal color varies from normal mucosal color to red or even yellow. Sometimes, they may be painful due to pressure effects and may compromise with normal physiological function due to mass effect. Intraoral NFs are mainly extra-osseous. However, in the mandible, intraosseous lesion has been described; they commonly arise in the posterior mandible and usually appear as unilocular or multilocular radiolucencies on radiographs with the differential diagnosis being that of cysts or odontogenic tumors. Oral NFs are nonodontogenic tumors, and the differential diagnosis is that of other lesions of the hard palate such as schwannoma, fibroma, traumatic neuroma, lipoma, or salivary gland tumor.
Microscopically, NF and schwannoma have close resemblance as both contain elongated cells with irregular nuclei lying between the bundles of collagen fibers. The origin of schwannoma is from the Schwann cells surrounding the nerve whereas that of NF is from the fibroblasts of the perineurium. Schwannoma consists of a mixture of Schwann cells, perineural cells, and endoneurial fibroblasts, and it is capsulated whereas NF is unencapsulated. Immunohistochemical analysis is useful for the confirmation of NF and helps to distinguish it from other benign neural lesions. NFs are immunopositive for the S-100 protein in 85–100% of the cases, indicating its neural origin.,, This was also seen in our case.
Asaumi et al. in their study described ultrasonography, CT, and magnetic resonance imaging as useful diagnostic and treatment tools for the estimation of tumor margins and the determining infiltration to surrounding structures. For bony erosion due to a malignant tumor, CT scans are useful. The role of plain film radiography or orthopantomogram is limited and may be used for determining the extent in cases of intra-osseous lesion. Since most intraoral tumors present early and are small, magnetic resonance imaging should not be mandatory.
The treatment for solitary NF is complete surgical excision. However, recurrence is common due to noncapsulated and infiltrative nature of the disease. This can be reduced by complete surgical resection with tumor-free margin. The recurrence is seen in as many as 20% of the patients with a NF after complete resection and increases to 44% with subtotal resection. Total surgical excision may pose a challenge in the head and neck region due to infiltrative nature of the disease and difficulty increases all the more when there are multiple lesions as seen in NF-I. The risk of neurological deficits increases in such cases. Tracheotomy as an adjunct to surgery is useful in cases of large oral or oropharyngeal NFs and decreases the anesthetic difficulties. Intraosseous NFs often require radical surgery including hemimandibulectomy or en bloc excision of the mandible. The common complication encountered during surgery is hemorrhage. The role of radiotherapy is limited and may be used if the patient is not fit or unwilling for surgery; especially in solitary plexiform type, where radiotherapy may retard the growth and shrink the tumor.
Malignant transformation of benign NF is rare and more commonly it has been associated with radiotherapy-treated schwannomas. The most common associated malignancy is neurofibrosarcoma, also known as malignant Schwannoma, which is estimated to occur in about 5% of cases, it is an aggressive tumor, and the prognosis is poor. Therefore, continued surveillance after surgery is mandatory to look for any recurrence or malignant transformation.
| Conclusion|| |
Solitary NF is an uncommon benign tumor which needs to be differentiated from other neural lesions. Immunohistochemical analysis becomes mandatory. The entity has an excellent prognosis; however, long-term regular follow-up is warranted to look for recurrence and malignant transformation. Distinguishing between isolated NF and those associated with NF-I is also important because of difference in clinical behavior, treatment, and prognosis. The current treatment of NF is complete resection.
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[Figure 1], [Figure 2], [Figure 3]