Year : 2008 | Volume
: 12 | Issue : 2 | Page : 75--78
Intraoral solitary neurofibroma in an infant
Anjali Narwal, Susmita Saxena, Vanita Rathod, Puja Bansal
Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut, U.P, India
Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut - 250 002, U.P
Neurofibroma is a non-circumscribed, thick and irregular benign tumor of the peripheral nerve sheath. On the skin, the diffuse and soft nature of neurofibroma often resembles «DQ»a bag of worms«DQ». It can develop at any point along a nerve and often form by late adolescence. Although neurofibromas occur predominantly as a feature of neurofibromatosis affecting the soft tissue, a few cases of solitary intraoral neurofibromas have also been reported. Solitary intraosseous neurofibroma in the oral cavity is a rare benign tumor with very few cases reported in literature. This case report presents a case of intraosseous solitary neurofibroma of maxilla in a 5-month-old male child due to the rarity of this tumor at this site in very early age, along with a discussion of its clinical, radiological, and histopathological presentation.
|How to cite this article:|
Narwal A, Saxena S, Rathod V, Bansal P. Intraoral solitary neurofibroma in an infant.J Oral Maxillofac Pathol 2008;12:75-78
|How to cite this URL:|
Narwal A, Saxena S, Rathod V, Bansal P. Intraoral solitary neurofibroma in an infant. J Oral Maxillofac Pathol [serial online] 2008 [cited 2021 May 17 ];12:75-78
Available from: https://www.jomfp.in/text.asp?2008/12/2/75/44583
Neurofibromas are the most common benign neoplasms of peripheral nerve. They are non-encapsulated, engulf the nerve of origin and have the potential for malignant transformation.  They appear clinically as soft, drooping and doughy masses.
Neurofibromas are derived from the cells that constitute the nerve sheath and are composed of neurites, Schwann cells, and fibroblasts within a collagenous or myxoid matrix. The cell of origin for neurofibroma has not been definitively identified, but is believed to arise from the perineurial fibroblasts which are neuroectodermal in origin.
Neurofibromas are the hallmark of neurofibromatosis, also known as von Recklinghausen's disease (VRD). Neurofibromas may occur as solitary lesions or as part of a generalized syndrome of neurofibromatosis (VRD) or very rarely as multiple neurofibromas without VRD. Solitary neurofibroma is a localized neurofibroma that, by definition, occurs in a patient who does not have neurofibromatosis.  Despite their occurrence in the head and neck region, neural sheath tumors are rarely seen in the oral cavity. Only 4-7% of patients affected by neurofibromatosis display oral manifestations. Tongue and buccal mucosa are the most common intraoral sites for neurofibromas though cases have also been reported to occur on the lips and gingival. 
An extensive search of the literature yielded only one case of a solitary neurofibroma arising from the soft palate; this patient presented with insidious tumor enlargement that had led to difficulties in swallowing and speech. In 2002, Surwald et al. reported the first case of solitary neurofibroma of the palatine tonsil, which occurred in a 28-year-old white woman in the United Kingdom. 
Majority of intraosseous forms of solitary neurofibroma reported are in the posterior mandible and a few in maxilla. This predisposition of intraosseous neurogenic tumors to occur in the mandible may be attributable to the thick bundles of inferior alveolar nerve.
The reported cases of solitary intraosseous neurofibroma of the jaws are few in the literature  and one such case affecting an infant is being reported.
A 5-month-old male child was brought by his mother to the Department of Oral and Maxillofacial Surgery with a chief complaint of painless swelling in upper anterior alveolar region since 4 months. It had grown slowly to attain the present size of about 2 x 2 cm. This pinkish red swelling was clearly evident on inspection and was firm, nontender, non reducible and nonpulsatile on palpation. The diffuse swelling was obliterating the nasolabial fold extraorally and the patient had incompetent and everted upper lip. Intraorally the swelling extended from right anterior maxillary canine region to the palate [Figure 1].
The patient was moderately built and nourished, with no difficulty in suckling milk. The patient had no similar swellings elsewhere in the body. Family history did not reveal any similar complaints in immediate or distant relatives.
CT scan on axial section showed a radiolucent mass enclosed by radiopaque expanded alveolus [Figure 2]. This radiolucent mass measuring 2 x 1 cm extended from the right anterior maxillary alveolus to the right lateral surface of nose.
An incision biopsy showed densely arranged collagen fiber bundles with plump active fibroblasts interspersed with parallel nerve fiber bundles having wavy nuclei [Figure 3]. van Gieson staining showed red collagen bundles interspersed with yellow stained neural tissue [Figure 4]. Silver nitrate and gold chloride staining showed thick black nerve bundles, thin black nerve fibrils and yellow collagen fibers [Figure 5]. Based on these findings a diagnosis of neurofibroma was given.
Immunohistochenistry, showed that the lesional tissue was positive for S100 and the perineural cells were negative for epithelial membrane antigen (EMA) [Figure 6] and [Figure 7]. EMA was investigated to rule out plexiform neurofibroma, which is a common finding in neurofibromatosis.
Complete excision of the lesion was done along with the adjacent healthy tissue. Healing and recovery of the patient was uneventful. A follow up period of one year was observed after excision during which no recurrence was seen.
Neurofibromas are benign, expansile swellings, contained within the epineurium. They are spindle cell tumors with a bland cytologic appearance, serpiginous nucleo-cytoplasmic contours and infiltrative poorly delimited boundaries. 
Neurofibromas are said to be indicative of VRD even though it may be the only manifestation of the disease. Neurofibromas, usually associated with VRD, are generally encountered as multiple lesions, and rarely occur as a solitary tumor. Since neurofibromas are usually multiple lesions, the whole body must be examined in addition to the larynx and trachea in patients with oral neurofibroma, since lesions in the upper airway may cause respiratory obstruction.
Neurofibromatosis is a disease entity that includes two distinct variants that differ from each other genetically, histologically and clinically - type I and type II. Neurofibromatosis type1 (NF-I), often known as von Recklinghausen's disease (VRD), is one of the most common autosomal dominant inherited disorders, with an incidence of 1 in 3,000. Neurofibromas are the most common benign tumors of NF-I. The NF-I gene is a large complex gene, the mutation of which gives rise to diverse manifestations in terms of gene organization and expression. The protein encoded by this gene (neurofibromin) is expressed in many different tissues and acts as a GTPase activator, and its absence leads to severe developmental abnormalities. 
Solitary neurofibroma is similar to the disseminated or the multiple form seen in VRD except that systemic and hereditary factors present in disseminated form are absent in this form. 
As per literature, around 40 cases have been reported as solitary intraosseous neurofibromas. Majority of the intraosseous lesions reported are in the posterior mandible and a few in the maxilla, with the female to male ratio being 2:1. 
Since the present case did not show any of the features used as diagnostic criteria for NF-1 except the presence of intraoral lesion, the diagnosis of neurofibromatosis was excluded. The patient had only a solitary lesion on the maxillary alveolar ridge, which caused him no discomfort. Although neurofibromas are slow growing tumors, in the present case the tumor showed a rapid growth within a short period of 4 months.
On histopathological examination of H and E stained sections of the biopsied tissue, hypercellular stroma with numerous spindle shaped cells and minimum amount of collagen bundle formation were seen. To differentiate this lesion from connective tissue tumors like myofibromatosis and desmoplastic fibroma, special stains were used i.e. van Gieson and silver nitrate. van Gieson staining distinguished densely packed collagen bundles from nerve bundles. Bright red stained collagen fibers were less as compared to the yellow stained bundles of tissue with parallel spindly nuclei.
Histochemical staining by silver nitrate with gold chloride showed increased number of thick black nerve bundles and a few yellow stained collagen fibers, confirming the diagnosis of neurofibroma.
Nerve sheath cells of the peripheral nerve consist of Schwann cells, perineurial cells, and endoneurial fibroblasts. These cells exhibit characteristic ultrastructural features and immunophenotypes. S-100 protein and EMA are known as specific markers for Schwann cells and perineurial cells, respectively. Among the immunohistochemical markers for nerve sheath cells, S-100 protein was introduced in immunohistochemistry very early and is still a useful marker for Schwann cells. There is proliferation of all the elements of the peripheral nerve - Schwann cells, axons, perineural cells (plexiform type) and fibroblasts in neurofibromas. Hence 30-40% of tumor cells are positive to S100 protein. Axons are neurofilament positive.
Neurofibroma is immunoreactive for S-100 protein. This immunological marker was positive in the present case. The Schwann cells showed positivity for S-100 protein.
EMA positive staining for perineurial cells is suggestive of plexiform neurofibroma. Since this EMA was negative in the present case, it helped us to rule out VRD in which plexiform neurofibroma is a common finding. S-100 positivity and EMA negativity were suggestive of solitary neurofibroma.
The lesion was completely excised after the establishment of diagnosis and there was no recurrence of the same lesion or any new lesion in the child during the follow up period of 1.5 years.
No genetic studies were performed and only the absence of any other lesion during the time period of one and a half year excluded its association with neurofibromatosis.
Early diagnosis in such a patient is very important and such patients need regular follow up during their lifetime to check for recurrences and appearance of other manifestations of VRD, especially central nervous system tumors.
The peak incidence of occurrence of neurofibroma is late adolescence but they also do occur during early infancy as it was seen in this present reported case. Hence by this case report we would like to highlight that intraosseous neurofibroma may be seen manifesting in the oral cavity at such an early age though its incidence is very rare.
The propensity of neurofibromas to progress to neurofibromatosis or the primary disease undergoing malignant transformation (6-29%) has been reported in the past. This progressive nature of the disease emphasizes the importance of close monitoring of patients presenting initially only with neurofibroma. 
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