Metastasizing pleomorphic adenoma in the mandibular bone: A Case Report

Introduction: Pleomorphic adenoma(PA) is known as the most common salivary gland tumor. PA uncommonly undergoes malignant transformation and rarely metastasizes outside the salivary gland. The Metastasizing Pleomorphic Adenoma(MPA) accounts for only about ۱% of all malignant PA. Asymptomatic swelling with slow progression is the usual manifestation of this tumor. Case presentation: This is a case of a ۶۲-year-old female who complained about mild to moderate pain and an unhealed ulcer due to extractions of molar teeth after several months. The patient's history revealed that total excision of the parotid gland was performed ۷ years ago, and then radiotherapy was done. Furthermore, the submandibular gland was completely excised ۳ years ago; Both times, pathology has reported Pleomorphic adenoma. In the intra-oral examination, swelling and expansion from the ascending ramus to the premolar area of the mandible were observed. A crater-like ulcer on the mandibular ridge and also necrotic areas on the lingual side of the swelling were inspected. On panoramic and CBCT, there was a large, ill-defined, lytic lesion in the left mandible from the distal of the premolar region to the ascending ramus. In histopathological evaluation, the tumor demonstrated classic features of a PA with proliferation of epithelial cells and diffuse islands of cartilaginous metaplasia. Although mitotic figures and nuclear pleomorphism were present, but the tumor is not malignant histologically. All the findings confirmed the diagnosis of Metastasizing Pleomorphic Adenoma. A complete surgical excision was done by a head and neck surgeon. In surgery, hemi-mandibulectomy, osteotomy of the pathologic lesion in the mandible, selective bilateral lymph nodes dissection, excision of jugular chain lymph node, reconstruction of Left mandibular bone defect, and check defect were done. Finally, a tracheostomy tube was inserted and planned for following up the patient.

کلیدواژه ها:

Metastasizing pleomorphic adenoma ، Parotid gland ، Pleomorphic adenoma ، Salivary gland