A Case of Epithelial-myoepithelial Carcinoma of Parotid Gland that Caused Multiple Cranial Nerve Disorders

Abstract

Epithelial-myoepithelial carcinomas (EMCs) are classified as a low grade malignant tumor arising from the salivary gland and comprises approximately 1% of all salivary gland tumors. We report herein on a patient with EMC arising from the deep lobe of the parotid gland who presented with facial nerve paralysis as an initial symptom, and then developed otalgia and glossopharyngeal pain, and finally presented multiple cranial nerve disorders. A 76-year-old woman was referred to us because of right otalgia lasting for 2 years and abnormal lesions in her mastoid cavity seen on magnetic resonance imaging (MRI). She had developed right facial nerve paralysis 6 years before the first visit to us. On otoscopic findings, her right tympanic membrane appeared normal. MRI revealed multiple lesions in the right mastoid air cells and along the glossopharyngeal nerve, and there was suspicion of a faint shadow in the deep lobe of the parotid gland. Medical treatments for the glossopharyngeal neuralgia showed little effect. The patient developed right laryngeal paralysis, and then developed right soft palate and accessory nerve paralyses six to eight months after the first visit. A mastoidectomy was performed which revealed multiple tumors in the mastoid air cells without bone destructions. Histologically, the tumor was diagnosed as an epithelial-myoepithelial carcinoma arising from the parotid gland. Positron emission tomography revealed a metastatic lesion in her cervical spine and, therefore, she underwent carbon-ion radiotherapy. Eighteen months after the treatment, the tumor size was stable. It was presumed that the tumor developed in the deep lobe of the parotid gland, and then invaded the mastoid cavity causing the facial nerve paralysis, and finally infiltrated medially along with the internal jugular vein giving rise to multiple cranial nerve (IX～XI) disorders.