You are in: eMedicine Specialties > Plastic Surgery > HEAD AND NECK Parotid Tumors, BenignArticle Last Updated: Dec 19, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Sanford Dubner, MD, Assistant Clinical Professor, Department of Surgery, Long Island Jewish Medical Center, Albert Einstein College of Medicine Sanford Dubner is a member of the following medical societies: American College of Surgeons, American Head and Neck Society, American Society of Plastic and Reconstructive Surgery, and New York Head and Neck Society Coauthor(s): Ashley D Gordon, MD, Plastic Surgery Fellow, Department of Surgery, Division of Plastic SurgeryEmory University; Richard E Kirschner, MD, Research Director, Department of Surgery, Division of Plastic Surgery, Assistant Professor, Children's Hospital of Pennsylvania, University of Pennsylvania Editors: Lawrence Ketch, MD, FAAP, FACS, Head, Program Director, Associate Professor, Department of Surgery, Division of Plastic Surgery, University of Colorado Health Sciences Center; Chief, Pediatric Plastic, The Children's Hospital of Denver; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Jaime R Garza, MD, DDS, FACS, Consulting Staff, Private Practice; Al Aly, MD, FACS, Consulting Surgeon, Iowa City Plastic Surgery; Deepak Narayan, MD, FRCS, Associate Professor of Surgery (Plastic), Yale University School of Medicine; Chief of Plastic Surgery, West Haven Veterans Affairs Medical Center Author and Editor Disclosure Synonyms and related keywords: salivary gland tumors, salivary gland disorders SIGNIFICANCESection 2 of 10
  Salivary gland disorders are not a major public health problem in the Western world. Neoplasms of the salivary glands account for fewer than 3% of tumors in the US and only 6% of head and neck neoplasms. Salivary gland tumors in children are uncommon, but it should be emphasized that the frequency of malignant tumors is higher in children than in adults. All masses in children require thorough diagnostic evaluation. Benign masses of the parotid gland in children may be due to vasoformative abnormalities, cysts, inflammatory processes, or neoplasms. The most common intraparotid mass is the benign lymph node, as a significant number of lymph nodes are present in the parotid. The most common benign tumor in children is the hemangioma. Of the benign epithelial tumors, the mixed tumor (pleomorphic adenoma) is the most common. ANATOMYSection 3 of 10
The parotid gland is the largest of the major salivary glands. It arises as an epithelial proliferation from the lining of the oral cavity at 5 weeks postovulation. It lies in the preauricular region deep to the skin and subcutaneous tissue. The facial nerve (cranial nerve VII) divides the gland into the larger superficial and smaller deep component. The parotid duct (Stensen duct) courses from the anterior border of the parotid gland below the zygoma, crosses the masseter muscle and the buccal fat pad, and turns deep to penetrate the buccinator muscle, finally opening intraorally at a papilla opposite the second upper molar. The duct varies in length from 4.0-7.0 cm. The parotid tail extends inferiorly into the neck as low as the sternocleidomastoid muscle. Acinar cells of the parotid gland are primarily secretory and produce thin, watery saliva devoid of mucous. INCIDENCE AND ETIOLOGYSection 4 of 10
Approximately 2500 new cases of salivary gland neoplasms are diagnosed each year. Parotid neoplasms account for 80% of salivary neoplasms. Of parotid masses, 75% are neoplastic; the remaining 25% are nonneoplastic infiltrative processes, such as cysts and inflammation. Of parotid neoplasms, 70-80% are benign. Except for Warthin tumors, benign tumors of the parotid gland are more likely to occur in women than in men. The median age for occurrence of these tumors is in the fifth decade of life. Parotid tumors occur most commonly in Caucasians. The etiology of these tumors is unknown, but the possibility of an adenoma gene currently is under investigation for its involvement in the development of pleomorphic adenomas. The most common benign parotid tumor in children is the mixed tumor. HISTORY AND PHYSICAL EXAMINATIONSection 5 of 10
A thorough history and physical examination is important in the workup of parotid masses. The major goal in the evaluation is to determine or exclude the diagnosis of malignancy. History often is the most useful tool in distinguishing inflammatory from neoplastic masses. Characteristics of inflammatory conditions are sudden onset, pain, and systemic infection. The most common presentation is that of an asymptomatic mass (81%) noted incidentally while washing or shaving the face. Pain (12%) or facial nerve paralysis (7%) is less frequent and more likely is due to malignancy. Parotid masses occur most commonly in the lower pole, or tail, and in the superficial lobe of the gland. Physical examination most often reveals a mobile nontender mass that is firm and solitary. Evaluate the possibility of a deep tumor by intraoral examination, with attention directed to the tonsillar fossa and soft palate. Inspect the Stensen duct for the character of the salivary flow (clarity, consistency, purulence) and notation of redness, bulging, and irritation of the ductal orifice as part of the physical examination. Evaluate the skin, oral cavity, oropharynx, and neck for possible primary lesions or nodal disease. DIAGNOSISSection 6 of 10
Laboratory studies Hematologic and serologic tests are of little importance in the workup of salivary gland tumors. Radiologic studies Radiologic studies are involved minimally in the workup of an asymptomatic mass.
Biopsy Fine-needle aspiration may be a valuable pretreatment diagnostic test. Its overall accuracy is greater than 96%, with a sensitivity for benign tumors of 88-98% and a specificity of 94%. Its sensitivity for detecting malignant tumors ranges from 58-96%, and its specificity is 71-88%. Frozen sections are 93% accurate when performed at surgery, but their use is controversial, since diagnosis depends on the experience of the pathologist with regard to salivary gland tumors. The standard biopsy approach is a superficial parotidectomy with preservation of the facial nerve. For 80-90% of parotid neoplasms, this procedure is both diagnostic and therapeutic. For this reason, preoperative fine-needle aspiration biopsy is recommended, since it can change the clinical approach in up to 35% of patients. Lymph nodes can be enucleated, as can Warthin tumors, and sialadenitis does not require surgical intervention in most cases. CLASSIFICATIONSection 7 of 10
Classification of Benign Primary Epithelial Salivary Gland Tumors
Benign pleomorphic adenoma or benign mixed tumor
Warthin tumor (papillary cystadenoma lymphomatosum or adenolymphoma)
Oncocytoma
Monomorphic tumors
TREATMENTSection 8 of 10
Superficial parotidectomy is the treatment of choice for most benign tumors in the superficial lobe. Make every effort to preserve the facial nerve. Avoid enucleation (except for Warthin tumors and lymph nodes), since it greatly increases the likelihood of recurrence (up to 80%) and nerve damage. Deep lobe tumors demand total parotidectomy with preservation of the facial nerve. For recurrences, postoperative radiotherapy may be administered, with local control rates exceeding 95%. Surgical incision Parotidectomy incision should allow for adequate exposure and the most aesthetic result. The incision begins anterior to the superior root of the helix and descends anterior to the tragus. It then is directed behind the lobule of the pinna and can be carried down anteriorly onto the neck as dictated by the need for exposure. If a large soft tissue defect is created by the excision of the parotid tumor, numerous autologous or allograft tissues (ie, dermal grafts, fascial grafts, fat grafts, Alloderm) or synthetic substances may be used for filling these defects. Try to preserve a layer of tissue (the parotid fascia or SMAS layer) if it does not compromise the capsule of the tumor. This preservation is important so that a layer of tissue interposes between the cut salivary tissue and the skin. This has been shown to reduce the incidence of Frey syndrome (gustatory sweating). COMPLICATIONSSection 9 of 10
Parotidectomy can be performed with little morbidity and no mortality. Most serious complications result from damage to the facial nerve (either temporary or permanent paralysis). Injury to the greater auricular nerve results in hypesthesia of the ear. A slight loss of fullness and an increased prominence of the angle of the mandible may occur after superficial parotidectomy. Frey (auriculotemporal) syndrome results from aberrant regeneration of auriculotemporal nerve fibers to sweat glands in the skin. The result is sweating on the affected side of the face during mastication. Uncommon sequelae include salivary fistula, seroma, hematoma, and infection. REFERENCESSection 10 of 10
Parotid Tumors, Benign excerpt Article Last Updated: Dec 19, 2006 |
