Frozen Section

More than any of the other available diagnostic techniques, the way in which frozen section is used will determine its value. Some malignancies (e.g., squamous cell carcinoma) will be diagnosed with nearly 100% accuracy. Further definition for problematic lesions will depend in great measure on the experience of the pathologist and the surgeon. Implicit is a discussion with the pathologist at the time of frozen section of intraoperative tumor patterns. Clinical cues in T3 or T4 tumors (e.g., tumor interface with the facial nerve, discussed further under Facial Nerve) and pattern of extension (e.g., skin proximity) can reasonably infer malignancy in many instances. If the interpretation on frozen section is malignant and a benign neoplasm is subsequently diagnosed on permanent section, it is only problematic if inappropriately radical surgery is the endpoint. This is where surgical judgment plays such an important role.

Although a thorough knowledge of the recent literature can augment judgment, there is no substitute in this setting for experience. Wheelis and Yarington,4 reporting on 256 frozen section results, noted a 5% error in benign to malignant and four instances of incorrectly diagnosing cancer. Error rates as high as 25% have been reported on frozen section. However, in an isolated study, Hillel and Fee5 reported no misdiagnoses of malignancy on frozen section. If the important details as iterated above are considered, a problematic error on frozen section should not occur. Problematic again refers to inappropriately aggressive surgery (e.g., sacrifice of the facial nerve, muscle, or bone). If malignancy is diagnosed on frozen section with clinical correlation for T2 or greater staging, a total parotidectomy should be performed with sampling of adjacent lymph nodes. A normally functioning facial nerve, irrespective of tumor encasement, should not be removed. This prudent approach based on frozen section will almost uniformly serve the patient well. If there ever is a question that cannot be resolved with certainty, waiting for permanent sections and then returning, should it be necessary for more extensive surgery, is the only reasonable approach.

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