Diagnostic challenges of an unusually large schwannoma of the mandible: Report of a case

Abstract

Schwannomas are slow-growing, benign neoplasms arising from the Schwann cells and are commonly reported as peripheral tumors in the head and neck region. Central intramandibular schwannomas are extremely rare lesions. We report a case of intramandibular schwannoma in a 70 year old male patient. Panoramic radiography revealed a large, multilocular radiolucent lesion with distinct borders involving the right mandibular body and ramus. A complete excision was achieved by removing the tumor followed by reconstruction of the mandible. The clinical, radiological, and histopathological features are discussed within the context of this case.

Keywords: Intramandibular schwannoma; Mandible; Schwannoma.

Fig. 1

Pre-operative clinical presentation of the patient. (a) Right lateral extra-oral view of the mandibular body and ramus region. (b) Frontal extra-oral view of the maxillo-mandibular region revealing mild facial asymmetry on the right side. (c) Intra-oral view of the right mandibular quadrant showing a partially edentulous arch and minimal clinical swelling due to bony expansion and normal overlying mucosa. (d) Intra-oral occlusal view of the mandibular arch showing asymmetrical bony expansion on the right side in comparison to the left side.

Fig. 2

Pre-operative radiographic evaluation of the patient. (a) Panoramic radiograph revealing multilocular radiolucent lesion involving the right mandibular body and ramus, extending anteroposteriorly from the second premolar to the entire mandibular ramus. Obliteration of the mandibular canal could be appreciated. (b) Contrast enhanced computed tomographic (CT) image showing a coronal section through the lesion as it extends across the mandibular foramen into the pterygomandibular space. Enlargement of the mandibular foramen (marked with yellow circles) on the right side in comparison to the unaffected left side can be appreciated clearly. (c) Contrast enhanced CT image showing an axial section through the lesion as it extends across the mandibular foramen into the pterygomandibular space. Enlargement of the mandibular foramen (marked with yellow circles) on the right side can be appreciated in this CT section too.

Fig. 3

Intra-operative and post-operative clinical and radiographic presentation. (a) Surgical approach to the tumor through an extended sub-mandibular incision and exposure of the tumor. (b) Resected specimen of the tumor involving the right mandibular body and ramus regions showing areas of cortical perforation on the lingual side and the inferior alveolar neurovascular bundle along with enlargement of the mandibular foramen (white arrows). (c) Panoramic radiograph showing the mandible, post resection of the tumor and reconstruction using a reconstruction plate. (d) Intra-oral view of the right mandibular quadrant 3 years postoperatively showing satisfactory mucosal coverage at the resection site, acceptable mouth opening and no clinical signs for lesion recurrence.

Fig. 4

Histopathological findings. Hematoxylin and eosin stained sections reveal spindle cell tumor with prominent focal palisading, “Antoni A” and interspersed eosinophilic incomplete Verocay bodies (VB) (a, ×20, b, ×40). Almost all of the tumor cells demonstrated strong positivity for anti-S100 and anti-CD56 (c ×40).