Dissecting discrepancies in head and neck margin assessment: frozen versus permanent sections

Concordance between intraoperative frozen section (FS) and subsequent corresponding permanent section (PS) diagnoses is essential for quality patient care. Reported FS-PS discrepancy rates for head and neck (HN) cases average 3% to 4%, mostly due to inadequate sampling and interpretation errors. We sought to review our experience with FS and concordant PS from HN pathology cases diagnosed at a high-volume university medical center.

A concordance review was performed for intraoperative FS and corresponding PS of HN surgical pathology cases over a 3-year period. A focused analysis was performed on FS-PS discordances related to margin status (MS) control. The FS-PS discrepancies were classified as due to "sampling" or "interpretation."

In total, 2337 HN cases yielded 11 108 intraoperative FS diagnoses. The FS-PS concordance review identified 143 (1.29%) discrepancies. Of these, 82 (57.4%) were for MS control, with just over half due to "sampling." The FS slides generally represented a single top section taken from the tissue, with "sampling" discrepancies due to discordant diagnoses identified on a deeper cut of tissue on the PS slides. Common "interpretation" discrepancies included overlooking high-grade squamous dysplasia (HGD) present on the FS.

Our institutional intraoperative FS-PS discrepancy rate for HN pathology cases is 1.29% and well within the national quality standards. Our FS-PS discrepancy rate for HN cases related to MS control was mostly due to "sampling." Interpretation discordances included failure to report HGD on the FS slide. Based on our review, the FS-PS discrepancies for MS control did not have a major clinical impact on most patients.