Mucoepidermoid Carcinoma of the Parotid Gland Presenting as a Fungating Exophytic Mass: A Surgical Challenge Rooted in Extensive Nerve Encasement

Abstract

Parotid glands, which are predominantly composed of serous acini, are the largest salivary glands in the human body. Mucoepidermoid carcinoma (MEC) of the parotid gland is the most common parotid tumour that routinely presents as a painless, fixed mass below the ears. However, its presentation as a fungating mass remains exceedingly rare. Due to the intimate anatomical relationship between the parotid gland and the facial nerve, parotid malignancies can culminate in facial nerve palsy, posing an onerous surgical challenge. In this paper, we chronicle the case of a male who presented with a fungating/exophytic mass and facial nerve weakness. A superficial parotidectomy was performed, and the eventual histopathological workup divulged an advanced mucoepidermoid parotid carcinoma entirely encasing the marginal mandibular nerve. Consequently, the marginal mandibular nerve was sacrificed, alluding to the remarkable surgical challenge encountered. Clinically, this manifested as an impairment of the motor function in the patient's left lower lip.

Keywords: exophytic; marginal mandibular nerve; mucoepidermoid; parotid gland.

Figure 1. A depiction of the patient's exophytic, fungating parotid mass (red arrow). A Blair incision was thus planned, with the margins delineated preoperatively (yellow arrow).

Figure 2. An intraoperative image showing the Babcock holding the specimen artery forceps (black arrows) at the carotid artery after excising the tumour from the underlying cervical nerves.

Figure 3. An intraoperative image showing the digastric muscle (yellow arrow), the IJV (black arrow), and the SCM muscle (blue arrow).

IJV: internal jugular vein; SCM: sternocleidomastoid

Figure 4. The gross morphology of the resected specimen (orange arrow).

Figure 5. Postoperative image showing the wound closure achieved (red arrow).

Figure 6. An image obtained at the follow-up visit shows mild motor function impairment of the left lower lip (yellow arrow).