In designing an operation for the removal of benign tumors of the parotid gland, two important facts must be noted. First, although over 75% of parotid tumors are benign, the vast majority of these benign tumors are mixed tumors (pleomorphic adenomas). Simple enucleation of a mixed tumor is followed by a high recurrence rate. Often the recurrent mixed tumor will become malignant. Consequently, a wide margin of normal salivary gland must be excised around the benign mixed tumor. Second, although the parotid gland is not anatomically a truly bilobed structure, for purposes of surgical anatomy it may be considered to have a superficial and deep lobe with the branches of the facial nerve passing between these two structures. Consequently, it is feasible to excise the superficial lobe with preservation of the branches of the facial nerve. This dissection will be indicated for most patients who have mixed tumors of the parotid gland. A few mixed tumors will arise in the deep lobe of the gland. In these cases, perform a superficial parotid lobectomy in order to identify each of the facial nerve branches. Then, with preservation of the facial nerve, remove the deep lobe. The Warthin tumor (papillary cystadenoma lymphomatosum) does not require a margin of normal parotid tissue and may be enucleated. However, in most cases the surgeon will not be able to make a positive diagnosis of a Warthin’s tumor preoperatively so that most of these tumors will also require exposure of the facial nerve and a partial superficial lobectomy. Small mixed tumors may similarly require a dissection of the facial nerve only in the region of the tumor. Then the tumor may be resected with a good margin of parotid tissue by doing a partial superficial lobectomy.
KeywordsFacial Nerve Parotid Gland Pleomorphic Adenoma Mixed Tumor Mastoid Process
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