The Use of Frozen Section in the Excision of Cutaneous Malignancy

Frozen section is known to be a valuable tool in the setting of indistinct lesions, lesions in cosmetically or functionally important areas, and those with recurrent or residual tumors. Most non-Mohs surgery studies comparing frozen section with paraffin sections suggest a concordance rate of 85% to 90%, whereas studies with Mohs surgery often suggest concordance rates of 95% to 98%. We do not perform Mohs surgery at our institutions but feel that the accuracy of frozen section is relatively high. Frozen-section data from between 2005 and 2011 was analyzed, and a total of 150 cases was found and assessed. Most of the cases were basal cell carcinomas and squamous cell carcinomas, with most arising in the head and neck region. Half of the resections were for previous incomplete margins with the other half being primary excisions. The frozen section was accurate in 97.7% of the cases when compared with the formal paraffin sections. However, the incomplete rate was higher at 14.8% because of patients with known positive margins on frozen section and the use of less accurate techniques of specimen analysis. We feel that, when used appropriately, frozen section can be a reliable tool and that a negative result should provide the surgeon enough reassurance as to undertake immediate reconstruction.