|Year : 2016 | Volume
| Issue : 1 | Page : 52-56
Nonsyndromic solitary neurofibromas in the oral cavity: Case series and literature review
Asha Reddy Venkataswamy1, Shesha Prasad Ranganath1, Sri Manasa Challapalli1, Leeky Mohanthy2
1 Department of Oral Medicine and Radiology, The Oxford Dental College, Hospital and Research Centre, Bengaluru, Karnataka, India
2 Department of Oral and Maxillofacial Pathology, The Oxford Dental College, Hospital and Research Centre, Bengaluru, Karnataka, India
|Date of Web Publication||8-Sep-2016|
Shesha Prasad Ranganath
Department of Oral Medicine and Radiology, The Oxford Dental College, Hospital and Research Centre, Bommanahalli, Hosur Road, Bengaluru - 560 068, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Neurogenic tumors are rare in the oral cavity. Solitary neurofibroma is a rare benign nonodontogenic tumor which may present either as a solitary lesion or as part of the generalized syndrome of neurofibromatosis or von Recklinghausen's disease of the skin. Clinically, oral neurofibromas present as pedunculated or sessile nodules, with slow growth, mostly without pain or paresthesia unless a neural compression occurs. The diagnosis can be confirmed by histological examination. Immunopositivity for the S-100 protein indicates its neural origin. Surgical excision is the treatment of choice and the prognosis is excellent.
Keywords: Neurofibroma, nonodontogenic tumor, von Recklinghausen's disease
|How to cite this article:|
Venkataswamy AR, Ranganath SP, Challapalli SM, Mohanthy L. Nonsyndromic solitary neurofibromas in the oral cavity: Case series and literature review. J Indian Acad Oral Med Radiol 2016;28:52-6
|How to cite this URL:|
Venkataswamy AR, Ranganath SP, Challapalli SM, Mohanthy L. Nonsyndromic solitary neurofibromas in the oral cavity: Case series and literature review. J Indian Acad Oral Med Radiol [serial online] 2016 [cited 2019 Nov 20];28:52-6. Available from: http://www.jiaomr.in/text.asp?2016/28/1/52/189992
| Introduction|| |
Oral physicians often encounter tumors of neural origin in the orofacial region. They present a diagnostic challenge because most of them are painless, slow growing and benign. Malignant variants are rare with a propensity for local invasion, rather than distant metastasis often mimicking their benign counterparts, making the diagnosis complex. Clinically, neurofibromas present as pedunculated or sessile nodules affecting the mucosa. They can occur either as solitary nodules or be associated with generalized syndrome of neurofibromatosis also known as von Recklinghausen's disease of the skin. They also closely resemble and must be differentiated from papillomas, fibrous hyperplasia and schwannomas. The solitary form does not vary from the disseminated form except the fact that systemic and hereditary factors are absent. Neurofibromas are broadly classified as dermal (myxoid) and plexiform neurofibromas. Dermal neurofibromas arise from single peripheral nerve whereas plexiform arises from multiple nerve bundles. Plexiform neurofibroma occurs along the peripheral nerve and is associated with small branches of nerve resulting in poorly circumscribed and locally invasive tumor. They cause morbidity and disfigurement and appear as “bag-of-worms.” The suggested treatment is surgical excision. We present three cases of oral solitary neurofibromas at unusual sites not associated with neurofibromatosis type 1, along with the diagnostic challenges they posed.
| Case Reports|| |
A 16-year-old female complained of an asymptomatic mass in the right cheek since 1 year which gradually increased to the present size [Figure 1]. Examination of the lesion showed a swelling that was diffuse, present along the line of occlusion, and measured approximately 2 × 2.5 cm. The surface of the swelling was smooth, soft, nonmobile and normal in color. Based on the above mentioned findings, a working diagnosis of benign tumor of connective tissue origin
An ultrasound was performed which revealed a well-defined lobulated heterogeneous lesion measuring approximately 3.5 × 2.1 × 1.9 cm on the right buccal mucosa. The lesion was deep to the subcutaneous fat and superficial to the ramus of the mandible, with no increased vascularity or calcifications within the lesion suggestive of lymphangioma of the right buccal mucosa. Fine needle aspiration revealed a negative aspirate. To determine the extent of the lesion, magnetic resonance imaging (MRI) was performed which showed a lesion located in the right buccal mucosa with homogenous, hypointense signal at T1 and hyperintense at T2, with zygomaticus major muscle stretched laterally by the lesion. Based on the MRI findings, a radiographic diagnosis of lymphangioma/minor salivary gland tumor was considered.
After routine blood examination tests, the lesion was surgically excised under local anesthesia. The wound was sutured and the postoperative period was uneventful. The excised tissue was subjected to microscopic pathological examination. The histopathological analysis revealed a tumor composed of interlacing bundles of elongated cells with wavy nuclei, suggestive of plexiform neurofibroma. Neither the clinical finding nor the familial history suggested neurofibromatosis type I or poly glandular syndrome MEN III (MEN IIb). Therefore, the lesion appeared to be independent of these diseases.
A 42-year-old male patient was referred for evaluation of a painless mass which was solitary, well-defined, slow growing for 8 years and present over the maxillary left gingival mucosa. Examination of the lesion revealed a lesion measuring approximately 2.5 × 3 cm, pink in color, smooth, shiny, covering the labial surface of the left canine. It was sessile, firm in consistency and nontender [Figure 2].
Past dental history revealed that a similar swelling was present in the same area 10 years ago which was surgically excised. The lesion had recurred in the same region 2 years after the excision. A thorough medical history and examination ruled out the presence of any other swelling elsewhere in the body. Family history was negative for type I neurofibromatosis or MEN III. A provisional diagnosis of pyogenic granuloma was given and the lesion was surgically removed under local anesthesia. The excised lesion was subjected to microscopic pathological examination. The histopathological results revealed a diagnosis of neurofibroma.
A 28-year-old male presented with a swelling in the left anterior palate for 15 years. Swelling was sessile extending from teeth number 21 to 24 measuring roughly 4 × 3 cm which was smooth, soft and nontender [Figure 3]. Aspiration of the lesion yielded no fluid and teeth 11, 12, 13, 21, 22, 23, 24 and 25 were vital. A provisional diagnosis of a developmental cyst was suggested and a differential diagnosis of lipoma and neurofibroma were considered.
An intraoral radiograph revealed a rarefaction interdentally between teeth 22 and 23. There were no significant changes noted in occlusal radiograph. A computed tomography revealed a heterogeneously enhancing soft tissue attenuated lesion involving the mucosa of the hard palate and gingiva. The lesion was projecting into the oral cavity, showing scalloping with minimal erosion of the hard palate suggestive of a benign neoplasm. An excisional biopsy was performed and the lesion was subjected to histopathological examination. The results revealed a tumor composed of interlacing bundles of elongated cells with wavy nuclei, consistent with neurofibroma with margins positive for tumor cells. Immunopositivity for S-100 was noted. A thorough medical examination was conducted to rule out swellings or pigmentation elsewhere in the body. This was essential to exclude neurofibromatosis. The diagnosis of solitary palatal neurofibroma was confirmed.
| Discussion|| |
Neurofibroma is a benign tumor of the nerve fibers that may sometimes be found involving the orofacial region. It originates from the peripheral nerve sheath. When compared with various other neural lesions that affect the head and neck, it is common in occurrence. It is believed that the predisposition for tumor formation is genetic in origin with imbalance in protein regulation, which normally prevents tumor formation. Neurofibroma can manifest either as an intra or extraosseous swelling and can be solitary or multiple. All the cases presented here were extra osseous and solitary.
In general, oral neurofibromas have an incidence of 4 to 7% till date. Neurofibroma type 1 being the most common entity affects 1 in 3000–4000 people globally. It is usually seen in the third decade of life, although a wide range of occurrence between 10 months and 70 years have been reported, with a female predilection as observed by Cherrick and Eversole. According to Chen and Miller , the age of incidence is between 9 and 72 years. The present case series reported age range from 16 to 42 years, with 1 female and 2 male patients.
Sixty six neurofibromas in the facial region have been reported in literature with the following distribution: Tongue - 12; palate - 12; mandibular ridge/vestibule - 15; maxillary ridge/vestibule - 9; buccal mucosa - 10; lip - 4; mandibular intrabony - 2; and gingiva - 1. Buccal mucosa and tongue were the most common sites intraorally. The current cases revealed lesions on the buccal mucosa, gingiva, and palate.
Neurofibromas may be a part of generalized neurofibromatosis or von Recklinghausen's disease  and MEN III with multiple appearances on the skin or may manifest as a solitary lesion; therefore, it is important to rule out the above mentioned two entities. It usually appears as a nodular, well-defined, mobile or sessile mass with slow growth. It is usually painless, and occasionally pain or paresthesia may exist due to nerve compression. All the 3 cases reported here presented with no pain or parasthesia complicating the diagnosis. Differential diagnosis is elaborated in [Table 1].
Microscopically, the tumor is composed of an irregular pattern of proliferative spindle cells, with a stroma of collagen fibers and mucoid masses. Neurofibroma can also be of mesenchymal origin which derives itself from Schwann cells and perineural fibroblasts. Immunopositivity for the S-100 protein is seen in 85–100% of the cases, indicating its neural origin.,, The histopathology [Figure 4]a of all the cases confirmed that they were neurofibromas with immunopositivity for S-100 [Figure 4]b.
|Figure 4: Photomicrograph showing (a) Neural spindle cells (10× magnification) and (b) S100 staining|
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MRI is preferred to CT because more accurate information regarding the tumor extension is obtained by the former showing low or isointense at T1 and hyper or isointense at T2 with a well-defined and homogenous consistency.
Surgical excision is the treatment of choice in case of solitary lesions. Surgical excision of the tumor can be difficult sometimes as the growth can be interwoven through the nerve structure. Conservation of the nerve from which the tumor originates must be given importance.
Although recurrence is rare, literature review suggests a high rate of recurrence in the tumors located at the head and neck region. Repeated excision of the lesions may have high chances of predisposing them to malignancy. In the current case series, the second case presented a positive history of recurrence.
| Conclusion|| |
An array of lesions can manifest as oral swellings which may be odontogenic or nonodontogenic, benign or malignant in origin. Though oral neurofibromas are documented in literature, usually they are not considered fore front in enumerating the differential diagnosis of swellings commonly seen in the oral cavity. These tumors can show a varied clinical appearance, as encountered in the present case series. Moreover, solitary neurofibromas can be the first manifestation of neurofibromatosis type 1. Hence, a long term follow-up is mandatory.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]