Malignant mucoepidermoid tumor arising in the accessory parotid gland: a case report

The head and neck surgeon's fascination with parotid surgery arises from the gland's spectrum of histopathological presentations, as well as the diversity of its morphological features. A mass arising in the mid-cheek region may often be overlooked as a rare accessory lobe parotid neoplasm. This report serves to revisit the topic of accessory parotid gland neoplasms to emphasize proper management, particularly the surgical aspects, so that consequences of salivary fistula, facial nerve paralysis, and recurrence are avoided.

We report a case of mucoepidermoid carcinoma which was assessed pre-operatively as arising from the accessory parotid gland of a 11-year-old female. She had complained of a painless and round mass of the left cheek for a duration of 12 months. Sialography, ultrasonography, CT scan and MRI were performed preoperatively. Sialography revealed a small duct separating from the Stensen's duct. CT and MRI showed that the tumor with smooth outline was lying on the masseter muscle and detached from the main parotid gland. The preoperative diagnosis was an accessory parotid gland tumor. The tumor was removed without facial nerve injury via standard parotidectomy incision. The tumor was composed of mucous, intermediate and epidermoid cells. The pathological diagnosis was low-grade mucoepidermoid carcinoma.

Accessory parotid gland neoplasms are rare and may present as innocuous extraparotid mid-cheek masses. A high index of suspicion, prudent diagnostic skills (including fine-needle aspiration [FNA] biopsy followed by computed tomography [CT] imaging), and scrupulous surgical approach (extended parotidectomy-style incision and limited peripheral nerve dissection when possible) are the keys to successful management of these lesions.