Journal of

Case Reports and Images in Dentistry

 
     
Case Report
 
Intrabony schwannoma of the mandibular symphysis: A rare case report
Soukaïna Oujdad1, Mounia El Bouhairi2, Sofia Haitami3, Hicham El Attar4, Ihsane Ben Yahya5
1MD, Resident, Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco
2Oral surgery specialist, Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco
3Assistant Professor, Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco
4MD in Pathology and Laboratory Medicine, Moulay Driss 1st Laboratory, Casablanca, Morocco
5Professor and Head of the Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco

Article ID: 100016Z07SO2017
doi:10.5348/Z07-2017-16-CR-2

Address correspondence to:
Soukaïna Oujdad
28 Rue Aziz Bellal ex Masséna
Casablanca
Morocco

Access full text article on other devices

  Access PDF of article on other devices

[HTML Abstract]   [PDF Full Text] [Print This Article]
[Similar article in Pumed] [Similar article in Google Scholar]

How to cite this article:
Oujdad S, El Bouhairi M, Haitami S, El Attar H, Ben Yahya I. Intrabony schwannoma of the mandibular symphysis: A rare case report. J Case Rep Images Dent 2017;3:6–10.


ABSTRACT
Introduction: Schwannoma is a benign type of nerve sheath tumor not frequently reported in the oral cavity, representing only 1% of benign primary bone tumors of the jaws. The most common location is the posterior body and the ascending ramus of the mandible, following the path of the inferior alveolar nerve. The symphyseal location is considered exceptional. The present case is an intraosseous schwannoma located in the mandibular symphysis.
Case Report: A 31 years old male patient was referred to our department regarding a slow-growing swelling with no acute signs. Panoramic radiograph and CT scan revealed a unilocular radiolucency of 18x20x35 mm, and no involvement of the mental or the inferior alveolar nerves. The finding data suggested a benign lesion with a cystic appearance. After the surgical enucleation, the histopathological analysis reported the diagnosis of an intraosseous schwannoma. The patient did not experience any postoperative complications.
Conclusion: In encountering a symphyseal swelling, non-odontogenic lesions, such as schwannomas must be considered in the list of diagnosis.

Keywords: Intraosseous, Mandible, Neurilemmoma, Schwannoma, Symphysis


INTRODUCTION

Schwannomas are a benign form of peripheral nerve sheath tumors. They mostly affect the vestibulocochlear nerve, causing a unilateral hearing loss. In the oral cavity schwannomas have a 35% chance of occurring [1]. The most common intraoral sites are the tongue, followed by the palate, the floor of the mouth, the buccal mucosa, the gingiva, the lips, and the vestibular mucosa [2]. Intraosseous schwannomas on the other hand are extremely rare representing less than one percent of the benign primary bone tumors. The most common site of occurring is the posterior part of the mandible, following the course of the inferior alveolar nerve. Intraosseous schwannoma of the mandibular symphysis is exceptional [3] .


CASE REPORT

A 31-year-old male patient was referred to our department (oral surgery and pathology Casablanca, Morocco), by a private dental practitioner, regarding a slow growth swelling in the mandibular symphysis with approximately six months of evolution. The patient reported an asymptomatic swelling six months prior to the dental visit, as a minor enlargement of the bone on the buccal side of the inferior incisors. The swelling then increased slowly in volume, without ever being symptomatic. The past medical, family history and dental history of the patient was unremarkable. No history of oral swelling, trauma, or swelling in other parts of the body was reported the facial appearance was symmetrical with no swelling (Figure 1). A clinical intraoral examination revealed a discrete anterior buccal expansion extending from the mesial side of the 44 to the mesial side of 33 lined with a normal mucosa and no involvement of the lingual side. No vestibular obliteration was noticed (Figure 2). On palpation the lesion was compressible and non-tender. Pulp vitality testing was negative on the four inferior incisors. Panoramic radiograph revealed a well-delimited radiolucency with corticated border, located in the mandibular symphysis, and extending from 45–33. Vertically, the lesion included the apices of the said teeth up to 15 mm above the inferior border of the mandible the radiograph also showed discrete root resorption of the 45, 44 and 33 and important root resorption of the 43, 42, 41, 31 and 32 (Figure 3).

A computed tomography scan showed an 18x20x35 mm image and no involvement of the mental or the inferior alveolar nerves. It also showed a pronounced resorption of the teeth’s roots in contact of the lesion, and a cortical bone interruption on the buccal side (Figure 4).

The finding data suggested a benign lesion with a cystic appearance.

A fine needle aspiration test did not draw any cystic fluid or blood. Under local anesthesia a surgical exposure of the lesion was obtained by a buccal mucoperiosteal flap. The lesion was found to be well circumscribed and contained within a well vascularized dense fibrous capsule (Figure 5). The tumor was easily enucleated in toto.

Microscopic examination showed spindle-shaped cells isolated or arranged in loose bundles. Verocay bodies were seen. Multinuclear cells with some atypia were noticed, but no mitotic activity was observed. The presence of an abundant myxoid stroma with the presence of ecstatic hyalinized blood vessels was also reported (Figure 6A).

Immunohistochemical staining for S-100 protein was strongly positive (Figure 6B). The diagnosis of a benign intrabony schwannoma was then confirmed.

The patient did not experience any postoperative complications. A follow-up of six months showed a good soft tissue healing (Figure 7A), no signs of paresthesia, and the beginning of bone formation (Figure 7B).


Cursor on image to zoom/Click text to open image
Figure 1: Extraoral photography of the patient showing no sign of swelling and asymetria.



Cursor on image to zoom/Click text to open image
Figure 2: Intraoral photography revealing a discrete anterior buccal expansion extending from the mesial side of the 44 to the mesial side of 33 lined with a normal mucosa and no involvement of the lingual side.



Cursor on image to zoom/Click text to open image
Figure 3: Panoramic radiograph showing a well-defined unilocular radiolucent lesion in the anterior mandibular region, discrete root resorption of the 45, 44 and 33 and important root resorption of the 43, 42, 41, 31 and 32.



Cursor on image to zoom/Click text to open image
Figure 4: Computed tomography scan showing a radiolucent image of 18x20x35 mm in the symphyseal area of the mandible, root resorption of the 44, 43, 42, 41, 32, 31, and cortical bone interruption on the buccal side.



Cursor on image to zoom/Click text to open image
Figure 5: Peroperative image showing the well-encapsulated tumor.



Cursor on image to zoom/Click text to open image
Figure 6: (A) Microscopic image showing patterns of nuclei interleaving with acellular (H&E stain, x400) areas, and (B) Immunochemistry staining for S-100 protein (magnification: x200).



Cursor on image to zoom/Click text to open image
Figure 7: (A) A follow-up of one year showing a good soft tissue healing (B) Panoramic radiograph at six months follow-up showing bone formation and no sign of recurrence.


DISCUSSION

Schwannomas are rare benign neoplasms derived from the Schwann cells of the myelinated nerves [4].

The first microscopic description of the tumor was made by Jose Verocay in 1908, and was then named neurinoma. In 1935, Arthur Purdy Stout, provided an advanced description of its histopathology and named it ‘Neurilemmoma’. Presently, the terms schwannoma, schwann cell tumor, neurinoma, neurilemmoma and perineural fibroblastoma are being used synonymously [1].

Schwannomas are unusual in the oral cavity and their intraosseous localization is extremely rare, but when they occur, the course of the inferior alveolar nerve is the most common site [4][5]. In this case, the neoplasm was probably developed from the peripheral nervous plexus of the anterior region of the mandible.

The etiology of the schwannoma is unknown. It is believed to originate from a benign proliferation of Schwann cells inside a fibrous capsule, peripherally to the parent nerve. During this process the tumor growth may cause displacement and compression of the said nerve [6].

There are three mechanisms by which an intraosseous schwannoma may evolve:

  • Centrally within the bone
  • From the nutrient canal, producing canal enlargement
  • From the soft tissue or the periosteum, causing secondary erosion, then penetrating the bone [7]

The common clinical presentation of schwannoma is the painless swelling. Other clinical symptoms such as paresthesia, tenderness to touch and teeth mobility were also reported [4][5].

Radiographic presentations of schwannomas are usually non-specific but are suggestive of a benign process. In most reports, a unilocular radiolucency with well-defined corticated borders was described. Similarly to our case, root resorption, expansion, thinning and erosion of corticals were also reported [4][2].

The rarity of this lesion in the anterior area of the mandible makes preoperative diagnosis unlikely. In general, the diagnosis is confirmed histologically after the excision of the tumor [2][8]. In the present case, the roots’ resorption and pulp necrosis of the anterior inferior incisors was more suggestive of an odontogenic lesion. It was during the perioperative time, with the negative fine needle aspiration test and the presence of a fibrous capsule, that the diagnosis of an intrabony tumor was considered.

Histologic features of intraosseous schwannomas are characteristics and easily distinguishable thanks to the presence of two distinct tissues arrangement Antoni type A and B, and Verocay bodies [2][8][9].

Antoni A areas are highly cellular zones, punctuated by nuclei arranged in stacked alignements known as palisades. Whereas Antoni B bodies are less cellular, with a myxomatous stroma, and loosely arranged cells. Schwannomas usually show a coexistence of both Antoni A and Antoni B areas. Verocay bodies consist of stacked arrangements of two rows of elongated palisading nuclei that alternate with acellular zones. The formation of this structure is explained by the overexpression of laminins, which is normally found in the basement membranes of several types of cells including schwann cells [9].

Immunohistochemistry is another histological tool to identify schwannomas. Immunoreactivity to S-100 protein is known to be a pathognomonic feature [10]. Being a well-encapsulated lesion, the treatment of choice for schwannomas is the conservative surgical excision, with periodic follow-up. The evidence of recurrence or malignant transformation is uncommon [4][5]. In this case, the patient had a followed-up of one year, and until now showed no clinical or radiographic signs of lesion recurrence (Figure 8).



Cursor on image to zoom/Click text to open image
Figure 8: Panoramic radiograph at one year showing a complete bone formation and no signs of lesion recurrence.



CONCLUSION

In encountering a symphyseal swelling, non-odontogenic lesions, such as schwannomas must be considered in the list of diagnosis.


REFERENCES
  1. Chi AC, Carey J, Muller S. Intraosseous schwannoma of the mandible: A case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003 Jul;96(1):54–65.   [CrossRef]   [Pubmed]    Back to citation no. 1
  2. Meundi MA, Anekar J, A C R, Patil US, Mustafa SM. Intraosseous schwannoma of the maxilla mimicking a periapical lesion: A diagnostic challenge. J Clin Diagn Res 2015 Mar;9(3):ZD01–4.   [CrossRef]   [Pubmed]    Back to citation no. 2
  3. Nevilli BW, Damm DD, Allen CM, Bouquot JE. Oral & Maxillofacial Pathology. 3ed. Chapter. 12. Soft tissue tumours Philadelphia: WB Saunders Company; 2009. p. 526–28.    Back to citation no. 3
  4. Zhang L, Xia BQ, Sun H, et al. Intraosseous schwannomas of the jaws: 2 case reports and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol 2012 Dec;114(6):e13–7.   [CrossRef]   [Pubmed]    Back to citation no. 4
  5. de Lacerda SA, Brentegani LG, Rosa AL, Vespúcio MV, Salata LA. Intraosseous schwannoma of mandibular symphysis: Case report. Braz Dent J 2006;17(3):255–8.   [CrossRef]   [Pubmed]    Back to citation no. 5
  6. López-Carriches C, Baca-Pérez-Bryan R, Montalvo-Montero S. Schwannoma located in the palate: Clinical case and literature review. Med Oral Patol Oral Cir Bucal 2009 Sep 1;14(9):e465–8.   [Pubmed]    Back to citation no. 6
  7. Park Y, Kim YW, Yang MH, Kim EJ, Ryu DM. Neurilemmoma of the mandible. Skeletal Radiol 1999 Sep;28(9):536–9.   [CrossRef]   [Pubmed]    Back to citation no. 7
  8. Sahoo PK, Mandal PK, Ghosh S. Schwannoma of the hard palate. Natl J Maxillofac Surg 2014 Jan;5(1):39–41.   [CrossRef]   [Pubmed]    Back to citation no. 8
  9. Joshi R. Learning from eponyms: Jose Verocay and Verocay bodies, Antoni A and B areas, Nils Antoni and Schwannomas. Indian Dermatol Online J 2012 Sep;3(3):215–9.   [CrossRef]   [Pubmed]    Back to citation no. 9
  10. Rahpeyma A, Jafarian AH, Khajeh Ahmadi S, Sarabadani J. A schwannoma of the soft palate in a child: Histological and immunohistochemical features and surgical method. Iran J Otorhinolaryngol 2012 Spring;24(67):95–9.   [Pubmed]    Back to citation no. 10
  11. 24303393

[HTML Abstract]   [PDF Full Text]

Author Contributions
Khushboo Goel – Substantial contributions to conception and design, Acquisition of data, Analysis and interpretation of data, Drafting the article, Revising it critically for important intellectual content, Final approval of the version to be published
Ashish Shrestha – Analysis and interpretation of data, Revising it critically for important intellectual content, Final approval of the version to be published
Vinay Marla – Analysis and interpretation of data, Revising it critically for important intellectual content, Final approval of the version to be published
Iccha Maharjan – Analysis and interpretation of data, Revising it critically for important intellectual content, Final approval of the version to be published
Guarantor of submission
The corresponding author is the guarantor of submission.
Source of support
None
Conflict of interest
Authors declare no conflict of interest.
Copyright
© 2017 Soukaïna Oujdad et al. This article is distributed under the terms of Creative Commons Attribution License which permits unrestricted use, distribution and reproduction in any medium provided the original author(s) and original publisher are properly credited. Please see the copyright policy on the journal website for more information.



ABOUT THE AUTHORS

Soukaïna Oujdad is a Resident at the Department of Oral Surgery and pathology, Faculty of Dentistry of Casablanca, Morocco. She is currently preparing her postgraduate thesis about Oral lichen Planus. E-mail: soukainaoujdad@gmail.com

Mounia El Bouhairi is Oral surgery specialist, Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco.

Sofia Haitami is Assistant Professor, Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco. E-mail: shaik.ajas@gmail.com

Hicham El Attar is Pathology and Laboratory Medicine, Moulay Driss 1st Laboratory, Casablanca, Morocco.

Ihsane Ben Yahya is Professor and Head of the Department of Oral Surgery and Pathology, Faculty of Dentistry of Casablanca, Morocco.





  Home line About the Journal line Aim and Scope line Open Access line Archives
Apply as Editor line Apply as Reviewer line Submit Reviews - Editors line Submit Reviews - Reviewers
Instructions for Authors line Templates to Use line Copyright Form line Author Checklist
Online Submission line Email Submission line Submit Revision line Submit All Forms line Submit Page Proofs
Terms of Service line Privacy policy line Disclaimer line FAQ line Contact: Journal line Contact: Edorium Journals line Site Map
 
  Copyright © 2017. Edorium. All rights reserved.