Benign Tumors of Major Salivary Glands Treatment & Management

Experienced clinicians generally agree that surgical excision is indicated for all patients in whom a salivary gland mass develops, unless comorbid medical problems preclude such intervention. Ultimately, surgical excision permits definitive diagnosis and determines the need for any adjuvant therapy that may be indicated in malignant tumors.

Furthermore, surgery is recommended because given the location of these lesions in the head and neck, there are unique consequences that can arise from even a benign space-occupying mass or tumor, specifically related to loss of function, disfigurement, and the social isolation that may ensue from such issues.

Indications for more urgent surgical treatment of salivary gland tumors (SGTs) include the following:

• Mass of the face, neck, and floor of the mouth
• Presence of clinical signs of malignancy (eg, a rapid growth on a slow-growing tumor, bleeding, airway compromise due to larger tumors, and nerve dysfunction such as paresthesia)

Inflammatory infectious masses (eg, reactive or fungal) and lymphoma should be treated medically. When symptomatic, recurrent chronic gland infection (eg, parotitis) proves refractory to conservative medical or endoscopic (ie, sialoendoscopic) treatments, salivary gland excision is sometimes indicated.

Management of benign SGTs includes complete removal of the neoplasm with an adequate margin of tissue to avoid recurrence. This usually involves either complete removal of the gland in which the tumor developed or extracapsular dissection of the tumor within the affected gland. Excision is performed with general anesthesia and without paralysis. The endotracheal tube is usually positioned in the corner of the mouth opposite to the surgical field.

Parotidectomy

The key to parotidectomy is safe localization of the facial nerve at the main trunk proximal to the gland. The possibility of total parotidectomy should be included in the preoperative plan. When a malignant diagnosis has not been ruled out, there should also be preoperative discussion of the potential need to sacrifice the facial nerve, with immediate grafting, cervical lymphadenectomy, and mandibulectomy.

Superficial parotidectomy remains the initial procedure of choice for benign parotid gland tumors. A modified Blair incision (see the image below) is often used. The incision usually starts just anterior to the ear helix, extends inferiorly below the ear lobe, and then continues onto the neck, paralleling—but staying at least 2 cm below—the body of the mandible. Other approaches, including a facelift incision, have been described.

To avoid injury to the facial nerve, the surgical field is exposed broadly, with the sternocleidomastoid muscle and the posterior belly of the digastric muscle serving as anatomic landmarks (see the images below). Additionally, the cartilage of the external auditory canal is exposed, and the tragal pointer and the tympanomastoid suture line (a palpatory landmark) are used to direct careful dissection so that the main extratemporal trunk of the facial nerve can be visualized.

Once the main trunk is exposed, dissection is performed to expose, while avoiding injury to, the individual branches of the nerve and, ultimately, to excise the tumor (see the image below).

An optional electromyographic (EMG) facial nerve monitor may be used to permit stimulation of the nerve for confirmation of integrity as needed during dissection. Although this is an exceedingly rare scenario with dissection for benign tumors, if the tumor necessitates resection of a portion of the facial nerve, the nerve should be immediately repaired or reconstructed to afford the best chance of maintaining tone in the muscle or muscles being innervated.

Another potential complication is sacrifice of the greater auricular nerve causing loss of sensation to the ear lobule and surrounding skin. To avoid this, careful dissection through the subcutaneous plane is performed to permit identification and preservation of the nerve as the anatomy allows.

The facial hollowing and loss of facial symmetry that may result from tumor and gland removal can sometimes be addressed at the time of surgery by placing cadaveric human dermal matrix or even by rotating a portion of the nearby sternocleidomastoid muscle into the deficit. Other approaches using avascular fat graft (harvested from the patient’s abdominal wall) have also been described.

Postoperative gustatory sweating (Frey syndrome) is rare but may occur with aberrant innervation of cutaneous sweat glands with parasympathetic input originally meant for the saliva-producing cells after parotid surgery. Use of thick skin flaps, placement of cadaveric human dermal matrix, or both may mitigate this complication.

Recurrence of a benign tumor can be avoided with complete excision of the lesion. Enucleation should be avoided so as to minimize the chance of tumor spillage and seeding recurrence.

Submandibular gland surgery

Submandibular gland surgery is performed with the patient under general anesthesia with endotracheal intubation. Head rotation is to the opposite side of the tumor.

An incision at least 2 cm below the body of the mandible is made through the platysma to permit identification of the superficial layer of the deep cervical fascia. To avoid injury to the marginal mandibular branch of the facial nerve, a technique of dividing the facial vein and raising a fascial flap/plane may be employed to ensure that dissection is deep to the nerve. Other approaches include direct identification of the nerve to avoid injury during dissection.

Additional potential complications during submandibular gland or tumor excision are injuries to the hypoglossal nerve, the lingual nerve, or both.  This may result in disrupted motor function and decreased sensation to the ipsilateral tongue. Careful dissection with appropriate identification and preservation of these structures is recommended.