Subtotal Parotidectomy and Unilateral Lateral Neck Dissection (Levels II, III, and IV) for Right Parotid Mucoepidermoid Carcinoma Involving the Deep and Superficial Lobes and Extending into Parapharyngeal Space

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the salivary glands, predominantly affecting the parotid gland. It commonly presents as a painless neck mass. Diagnostic workup includes physical examination, imaging, and fine needle aspiration biopsy. Superficial, subtotal, or total parotidectomy, with or without neck dissection and possible adjuvant radiation therapy, is recommended in most cases according to tumor stage, grade, and adverse pathological features. In the case presented here, subtotal parotidectomy with facial nerve preservation and neck dissection followed by adjuvant radiation therapy was elected. Post-treatment imaging at three-month intervals showed no evidence of persistent disease. The attached video demonstrates subtotal right parotidectomy via combined anterograde and retrograde nerve dissection and right selective neck dissection of levels IIa, IIb, III, and IV.

Salivary gland neoplasm; parotid gland; neck mass.

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the salivary glands, predominantly affecting the parotid gland.¹ It typically presents as a painless, progressively growing mass, with higher grade cancers typically progressing more rapidly, invading local structures. Diagnostic work-up for parotid masses includes physical examination, imaging, and fine needle aspiration biopsy (FNAB) with cytology. Surgical resection (superficial, subtotal, or total parotidectomy) with or without facial nerve preservation, along with elective or therapeutic neck dissection, is recommended in most cases, with adjuvant radiation indicated in high grade cancers, advanced stage disease, or positive margins.²

The patient is a 43-year-old female with no prior history of head and neck cancers (HNC), who presented with a few months’ history of progressive and painful right facial swelling. Medical history included obesity (BMI 31.5), well-controlled asthma, and anxiety and depression.

On review of systems, she reported no chronic fever, illness, chills, night sweats, or weight loss. She had no history of smoking or alcohol or drug abuse.

FNAB demonstrated sheets of atypical oncocytic cells with disorganized architecture and both intracytoplasmic and extracellular mucin. The findings were suggestive of a low-grade mucoepidermoid carcinoma. FNAB from a mildly enlarged ipsilateral lymph node was negative for cancer.

Parotidectomy with elective neck dissection and anterolateral free flap reconstruction was discussed as the recommended treatment option.

Physical examination revealed an alert female in no acute distress. A large semimobile mass of about 6 cm by 5 cm was found over her entire right parotid gland extending down to her upper neck. At the apex of the mass, below the earlobe, the skin was indurated and not mobile. The facial nerve function was intact. No other neck masses were present. No other masses or lesions were found in the oral cavity or oropharynx.

Contrast-enhanced computed tomography (CT) demonstrated a complex infiltrating mass of approximately 4.5 cm within the right parotid, involving the superficial and deep lobes, with an adjacent circumscribed cyst and few prominent adjacent lymph nodes (Figures 1 and 2).

Figure 1. Preoperative CT soft tissue neck with contrast - axial view. Complex, cystic, solid, and heterogeneously-enhancing 4.5-cm mass involving most of the right superficial and deep parotid gland. Posterior to the earlobe, no fascial planes are present between the mass and the skin.

Figure 2. Preoperative CT soft tissue neck with contrast - coronal view.

CT thorax without contrast revealed no lymphadenopathy within the chest or lung nodules.

Salivary gland tumors can affect the parotid, submandibular, sublingual, or minor salivary glands, with parotid masses being most common (~70–80%).³ Pleomorphic adenomas are the most common benign salivary gland tumor, while MECs are the most common malignant salivary gland tumor.^1,4 MECs predominantly occur in women and those in their 40s or 50s.⁵ Individuals typically present with painless, progressively enlarging mass over the parotid region, with some patients developing pain, tenderness, or facial nerve weakness, mostly apparent in advanced disease.⁶ MECs typically exhibit aggressive growth, with low-grade tumors demonstrating slow growth over the years and high-grade tumors growing rapidly and infiltrating local structures (perineural, lymphovascular, or bone invasion).⁵ Without treatment, high-grade tumors can metastasize to the lungs, brain, or skeletal system.⁵ High-grade tumors result in worse outcomes, high recurrence rates, and increased risk of metastases.⁷

Surgical resection is the mainstay treatment for MEC and is usually sufficient for low- to intermediate-grade and early-stage cancers. High-grade and advanced stage cancers are usually treated with a more radical resection, elective or therapeutic neck dissection, and adjuvant radiation, rarely with chemotherapy. In cases of parotid MEC, various types of parotidectomy with or without facial nerve preservation is most common, with a more radical approach reserved for patients with high-grade tumors.⁶ Neck dissection is recommended for patients with locally advanced disease, clinical or radiological regional metastatic disease, or high-grade cytology.² Free flap reconstruction is necessary for patients with anticipated tissue/volume loss and facial deformity. Adjuvant radiation therapy is recommended for high-grade tumors, positive margins, advanced stage, adverse pathological features, or as first line modality for nonsurgical candidates.² Chemotherapy is usually of low benefit and not routinely offered.⁸

The goals of surgical treatment are to completely remove the MEC, preserve facial nerve function, and prevent recurrence. With surgery, it is pertinent to remove the tumor with negative surgical margins and perform thorough neck dissection of lymph nodes. Facial nerve preservation and free flap reconstruction is important for maintaining functioning, appearance of the face and neck, and quality of life. Routine oncological follow-up with physical examination and imaging is essential for detection of early recurrence.

Preoperative evaluation is key for proper surgical planning. In case of large cancers involving the deep parotid lobe, preoperative facial nerve functional deficits, large and fixed tumors or skin involvement, the surgeon should prepare for a radical resection, tissue loss, and possible facial nerve sacrifice that will mandate a collaborative team approach with the ablative surgeon and the reconstructive team for possible free tissue transfer, facial nerve grafting, tarsorrhaphy, etc..

Frequently, for high-grade and advanced-stage MEC of the parotid gland, near total/total parotidectomy with facial nerve preservation, when possible, is the gold-standard treatment to minimize recurrence and preserve function. In our 43-year-old patient, subtotal parotidectomy, selective neck dissection with facial nerve preservation, reconstruction with anterolateral free flap, followed by adjuvant radiation, was performed. 

After the patient was brought into the operating room, she was placed under general anesthesia and underwent orotracheal intubation. A right modified Blair incision extending down into the right lower neck in half-apron fashion was designed to include a 3 by 2 cm skin island inferior to the earlobe where the mass was adherent to the skin. Skin flaps were then elevated over the right parotid and neck. The mass displaced the main trunk and lower division of the facial nerve superiorly. It was adherent to the main trunk of the facial nerve, mastoid tip, and stylomastoid foramen, infiltrated the superior SCM, posterior belly of digastric, and stylohyoid muscles, which were all partially resected. It extended into the right parapharyngeal space, abutting the great vessels and the spinal accessory nerve. Ultimately, a subtotal right parotidectomy via combined anterograde/retrograde facial nerve dissection approach was performed to allow for en bloc resection of the mass along with safe facial nerve dissection and preservation. All branches of the facial were kept intact with brisk return of stimulation at 0.5 mA at the conclusion of the procedure. Right selective neck dissection of levels IIa, IIb, III, and IV was performed in a usual fashion. Operative time was 336 minutes with estimated blood loss of 20 mL. On post-op day three, the patient was noted to have an altered mental status with an unremarkable brain CT. Psychiatric evaluation confirmed an anxiety attack, which was resolved following administration of lorazepam. The postoperative length of stay was 6 days, and the patient was discharged without surgical complications. On her follow-up appointment, the patient had a small dehiscence posterior to the right auricle which resolved with conservative management. Facial nerve function was intact. 

Final pathology came back as intermediate-grade MEC pT3 N0 M0, negative for perineural or lymphovascular invasion. Due to positive deep margins, postoperative radiation was administered. Three-months interval post-treatment imaging demonstrated no evidence of persistent disease.

Nothing to disclose.

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.