Approach Considerations
The general consensus is that definitive surgical therapy is indicated for most benign tumors of the minor salivary glands. Notable exceptions to this would be certain tumorlike conditions, such as lymphoepithelial cysts associated with AIDS, as well as small asymptomatic hemangiomas. Historically, physicians have advocated surgery without radiographic imaging or fine-needle aspiration (FNA) cytology; current recommendations include preoperative assessment with these diagnostic tools to assess for locoregional extent and concomitant lymphadenopathy.
The primary contraindication for surgical treatment of benign salivary gland tumors is the presence of associated medical comorbidities that preclude the use of general anesthesia.
Medical Therapy
In cases of inflammatory or infectious salivary masses (eg, acute bacterial sialadenitis or mycobacterial infection), administration of appropriate medical and supportive treatment is warranted. Salivary gland excision is sometimes indicated when chronic, symptomatic, recurrent sialadenitis proves refractory to conservative therapies. If lymphoma is diagnosed, appropriate treatment for the stage and subtype of lymphoma is indicated through consultation from a medical oncologist.
Surgical Therapy
Management of benign salivary gland tumors includes complete removal with an adequate margin of peripheral tissue to avoid locoregional recurrence. This implies complete removal of the offending gland in whose native tissue the tumor has arisen. Excision is performed with the patient under general anesthesia without paralysis. The endotracheal tube is usually positioned in the corner of the mouth opposite the proposed surgical field.
Minor salivary gland resection
Surgical treatment of minor salivary gland tumors depends on the site of origin and the extent of locoregional disease. For tumors of the lip or palate, this may simply involve wide local excision with primary closure. Benign minor salivary gland tumors of the upper lip and buccal mucosa are often managed with a mucosa-sparing wide local excision that sacrifices the etiologic minor salivary gland tissue with an intact tumor pseudocapsule. [56]
For more extensive palatal lesions, the recommendation is to perform a bone-sparing, periosteal-sacrificing, wide local excision incorporating 5- to 10-mm linear margins within the palatal mucosa, with careful preservation of the tumor pseudocapsule. The periosteum and tumor pseudocapsule represent anatomic barrier margins on the deep surface of the tumor. In long-standing cases of benign palatal salivary gland tumors, the thin remaining bone is sacrificed on the deep surface of the tumor specimen; retention of thinned bone often is not technically possible or anatomically meaningful.
Immediate soft-tissue reconstruction of the resultant defect is possible and desirable; primary closure with adjunct locoregional flap reconstruction may be used if clinically indicated.
Transcervical approach
Larger tumors of the parapharyngeal space may necessitate a more complex surgical approach; intraoral resection typically is not recommended in such cases. The main options for external approaches to the parapharyngeal space are as follows:
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Cervical-parotid approach
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Cervical-parotid approach with mandibulotomy
Although this procedure does not require a full facial nerve dissection, the inferior divisions must be located and preserved. By retracting the sternocleidomastoid laterally, the surgeon can identify the internal jugular vein, the carotid artery, and the lower cranial nerves (IX-XII). For access to this space, the posterior belly of the digastric and stylohyoid muscles must be divided, followed by the external carotid artery (ECA) and the stylomandibular ligament. In addition, the styloid process may be resected for delivery of larger tumors and greater visualization.
Often, in the treatment of benign lesions arising from the minor salivary glands, an attempt is made to avoid a mandibulotomy. However, in patients with tumors located in the superior aspect of the parapharyngeal space that are approaching the eustachian tube and skull base, a mandibulotomy may be necessary in order to provide optimal surgical access. [57]
Transoral robotic surgery
Applications of minimally invasive transoral robotic surgery (TORS) to head and neck surgery have increased. There are case series of patients safely undergoing TORS for certain benign minor salivary tumors of the parapharyngeal space. TORS allows access to the parapharyngeal space and allows precise tumor dissection, avoiding the need for an external approach and thereby improving cosmetic outcomes for patients.
The risk of tumor capsule fragmentation and subsequent cellular spilling with TORS has been found to be low. However, depending on the location of the tumor, a change in approach to a transoral blunt instrument dissection may be necessary to avoid damage to the ECA and ensure patient safety. [58] TORS can be attempted for tumors medial to the ECA; however, a transcervical approach is taken for tumors located laterally. [59]
Complications
Complications associated with definitive excision and reconstruction of palatal minor salivary gland tumors (both benign and malignant) include the following [60] :
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Eustachian tube dysfunction
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Flap loss
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Trismus
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Velopharyngeal insufficiency
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Wound dehiscence
Complications associated with definitive transcervical excision of parapharyngeal minor salivary gland tumors include the following [61] :
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Facial nerve paralysis
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First bite syndrome
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Frey syndrome
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Hemorrhage
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Infection
Complications associated with TORS include the following [62] :
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Bleeding
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Dysphagia
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Aspiration-related infections
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Local pain
Age greater than 60 years and a larger extent of surgical resection are significant predictors of complications.
Diet
A regular diet may be resumed after excision of most benign salivary gland lesions. More extensive excisions may warrant adherence to a soft diet for 7 days. Patients are counseled to avoid spicy or acidic foods for 7 days while the reapproximated mucosa heals. Postoperative oral hygiene is also recommended, with routine saline rinses after meals.
Prevention
Dietary alterations may be effective in preventing salivary gland tumors by increasing consumption of fruits and vegetables, particularly those high in vitamin C, and by limiting intake of food that is high in cholesterol. [63] A case-control study conducted in China revealed a significant protective effect of consumption of dark-yellow vegetables or liver, with a 70% reduction in the risk of salivary gland malignancy among the subjects with the highest intake of these particular types of foods. [64]
Long-Term Monitoring
Patients should be followed at intervals of 1 week, 4 weeks, and 12 weeks postoperatively to monitor wound healing, as well as to look for any new symptoms related to the surgical resection or reconstruction. After this period, given the benign salivary pathology, patients may be monitored by their primary care provider at regular intervals until new symptoms or lesions develop for which repeat referral is warranted.
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Histologic architecture of the salivary gland unit.
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Coronal magnetic resonance imaging (MRI) scan demonstrating a large, benign lesion of the right parapharyngeal space.
