Malignant parotid neoplasms represent 1 to 3% of carcinomas of the head and neck. Recurrence of these malignancies is often synonymous with future therapeutic failure. Identifying the covariables suggestive of aggressive behavior and recurrence could alter initial therapeutic planning. Tumor stage, including extension, facial nerve involvement, and histologic grading are the most significant prognostic indicators.1 Integrating the aforementioned into a realistic therapeutic plan is still best accomplished by case individualization, with decision making reflecting significant physician experience. Some points as to data acquisition and interpretation follow. The realities of cost containment are reflected in the management strategies proposed but are not further specified.

MRI and CT

Magnetic resonance imaging (MRI) and computed tomography (CT) are sophisticated techniques, each with independent strengths. However, rarely do these procedures alter the decision to perform surgery. Their relative value is in evaluating the extent of larger tumors, and associated nodal status and in differentiating deep lobe neoplasms from primary parapharyngeal space lesions.² Although some controversy exists as to which provides the most meaningful data, MRI in most situations appears to have some advantages. For soft tissue definition, resolution is generally superior. Further, some neoplasms have identifying characteristics noted on MRI studies. Warthin’s tumors, for example, are well marginated and heterogeneous, whereas pleomorphic adenomas are homogeneous and smoothly marginated. Differences in signal intensity have been noted for low- and high-grade malignancies. If bone and/or skull base definition is needed, CT can be added as an adjunct to MRI. It should be stated that there is no longer a need for radionuclide imaging or sialography in the management of parotid neoplasms.

For the isolated easily palpable parotid mass, preoperative imaging is not a necessity. Imaging studies are beneficial preoperatively in defining the extent of larger infiltrative tumors. MRI is the initial imaging modality of choice.

Fine-Needle Aspiration Biopsy

Three alternatives are present when considering FNAB. First, the choice not to use FNAB as a diagnostic technique rests with the premise that it will not alter management. Second, proponents of routine use want to have as much information as possible available preoperatively for counseling patients, often with reference to facial nerve management. Third, selective use of FNAB depending on the situation, which would appear to have the most merit. Any advantage conferred by having FNAB data depends entirely upon the accuracy of the information obtained. The latter unquestionably is experience driven, both in performing the procedure itself and in the interpretation thereof. It is acknowledged that FNAB is better at identifying and classifying benign lesions. Today, in 93% of cases, it is possible to differentiate benign from malignant. However, it is clearly more difficult to classify the malignant group with this technique.³ The difficult question as to the value of FNAB is whether it alters decision making. Further, with a small but acknowledged false-positive rate, should a more aggressive surgical procedure be performed based primarily on FNAB data? The answer is, selectively, yes. For example, squamous cell carcinoma should be readily identifiable on FNAB. Mucoepidermoid tumors can often be identified as well. Appropriate preoperative counseling could then be given, with intraoperative frozen-section confirmation leading to an appropriate surgical procedure. It is interesting, however, that a recent survey of 34 head and neck surgeons found that FNAB data did not alter decision making for a discrete parotid mass.³ In such a setting, patient and physician comfort with the clinical preoperative information gleaned from the history and physical examination will be the final arbiter as to the value of FNA for the isolated parotid mass.

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