American Journal of Medical Case Reports, 2014, Vol. 2, No. 10, 222-224 Available online at http://pubs.sciepub.com/ajmcr/2/10/6 © Science and Education Publishing DOI:10.12691/ajmcr-2-10-6 Malignant Peripheral Nerve Sheath Tumor of Buccal Mucosa: An Oncological Surprise Ram Abhinav Kannan 1,* , Kirthi Koushik 1 , Usha Muniyappa 2 , Ritika Harjani 1 , Arvind Murthy 1 1 Department of Radiation Oncology, M S Ramaiah Medical College, Bangalore, India 2 Department of Pathology, M S Ramaiah Medical College, Bangalore, India *Corresponding author: dr.ramabhinav@gmail.com Received September 08, 2014; Revised October 10, 2014; Accepted October 20, 2014 Abstract Malignant peripheral nerve sheath tumors are aggressive sarcomas with poor prognosis. It is usually encountered in lower extremities. Only a few cases have been reported in head and neck region with buccal mucosa being an unusual site. Keywords: malignant peripheral nerve sheath tumor, radiation, surgery Cite This Article: Ram Abhinav Kannan, Kirthi Koushik, Usha Muniyappa, Ritika Harjani, and Arvind Murthy, “Malignant Peripheral Nerve Sheath Tumor of Buccal Mucosa: An Oncological Surprise.” American Journal of Medical Case Reports, vol. 2, no. 10 (2014): 222-224. doi: 10.12691/ajmcr-2-10-6. 1. Introduction Malignant peripheral nerve sheath tumors (MPNSTs) are spindle-cell sarcomas which are aggressive tumors accounting for 5–10% of all soft tissue sarcomas. These tumours are usually found in the lower extremities, with retroperitoneum being next most common site [1]. Only 8–16% of MPNSTs develop in the head and neck region. The oral cavity is an unusual site for this tumor [2]. In this paper, we report a case of MPNST arising from the buccal mucosa along with available review of literature. Figure 1. Heterogeneously enhancing lesion in left buccal mucosa, medially abutting the tongue and posteriorly abutting the submandibular gland and massetter 2. Case Report A forty year old female presented with complaints of swelling in left side of her mouth that gradually progressed over 3 months. She also gave history of mass in the same region two years back, for which she underwent left mandibular resection along with plate reconstruction, which was diagnosed as ameloblastic fibroma on post- operative histological examination. Examination of oral cavity revealed a 3X3 cm mass in the left buccal mucosa with extension to left lateral border of tongue. Computed tomography scan (CT scan) with intravenous contrast revealed a heterogeneously enhancing lesion in the left buccal mucosa measuring 3.7 X 3.3 X 3.1 cm (Figure 1). The lesion was abutting the tongue medially with mild assymetrical enhancement of the tongue and posteriorly, the lesion was abutting the submandibular gland and massetter. A lymph node measuring 1 X 1 cm was noted in the left submandibular region. Biopsy of the tissue mass showed tumor cells which are predominantly round to oval with few spindle shaped cells having large vesicular nuclei and moderate to scanty eosinophilic cytoplasm with numerous mitotic figures, suggestive of sarcoma or a poorly differentiated carcinoma (Figure 2, Figure 3). Immunohistochemistry revealed tumor cells strongly positive for vimentin, S-100 and are negative for pan-CK, CD 34, desmin and smooth muscle actin (Figure 4). The histopathological examination and immunohistochemistry was consistent with the diagnosis of malignant peripheral nerve sheath tumor. CT scan thorax and ultrasound of the abdomen was negative for distant metastasis. There was no history suggestive of neurofibromatosis. Patient underwent extended hemi-mandibulectomy and ipsilateral neck node dissection under general anaesthesia. The resected tumor measured 4.5 X 4 X 2.5 cm with posterior, medial and inferior mucosal margins being involved by the tumor.