AAO-HNSF Primary Care Otolaryngology Handbook

CHAPTER 13

parotid. A variety of diagnostic studies can be performed. Physical exam, radiographic imaging, and fine-needle aspiration are adequate for diag- nosing 95 percent of parotid masses (Figure 13.1). However, surgical removal with superficial parotidectomy remains the final diagnostic step of choice.

Parotid masses are traditionally resected with a superficial parotidectomy for two reasons. First, it is quite easy to damage the facial nerve branches unless the mass is traced from its origin through its entire course in the gland. Second, the most common type of salivary tumors (pleomorphic adenoma) tends to recur, and this procedure allows the surgeon to get a good margin of normal tissue around the tumor in order to decrease the recurrence rate. It is important that masses in this region not be enucleated, since injudicious excision can result in both facial nerve injury and recurrent tumor. Recent studies have shown though that, in the hands of an experienced surgeon and depending on tumor size, location, and pathology, extracapsular dissection may be an equally safe alternative to the traditional superficial parotidec- tomy. Total parotidectomy, with preservation of the facial nerve, removes both the superficial and the deep lobes of the parotid, and may be required in some conditions. If cancer has invaded the facial nerve, sacrifice of the nerve may be required.

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Figure 13.1. Right parotid mass. Eighty percent of parotid neoplasms are benign, pleomorphic adenomas; however, 20 percent are malignant. Diagnosis can often be made by a fine-needle aspiration of the mass. Excision of benign tumors requires superficial parotidectomy and facial nerve dissection.

A Few Basic Principles about Salivary Gland Tumors The larger the salivary gland, the less likely the tumor is to be malignant. Thus, a mass in the parotid has only a 20 percent chance of being a malignant tumor, a mass in the submandibular gland has a 50 percent chance, and a mass in the sublingual gland has a 75 percent chance. The most common benign tumor of the salivary glands is a pleomorphic adenoma (also known as mixed tumor ). The most common malignant tumors are adenoid cystic carcinoma and mucoepidermoid carcinoma . Adenoid cystic carcinoma has a strong propensity to invade nerves and track along them. This is significant, because the seventh cranial nerve tracks right through the parotid gland. The lingual and hypoglossal nerves are very close to the submandibular gland.

Primary Care Otolaryngology