Excision of periocular basal cell carcinoma guided by en face frozen section

We describe a technique for monitoring excision margins in periocular basal cell carcinoma (BCC) using en face frozen sections and report outcomes. We excised periocular BCC with 3mm margins. An outer 1mm sliver of the perimeter of the specimen was mapped and sent for evaluation by en face frozen section. The central tumour mass was processed using routine paraffin sections. A further 3mm level was excised at the site of any affected margin and the outer 1mm sliver was again evaluated by frozen section. We identified 78 patients from November 2003 to July 2009; 67 had primary tumours and 11 (14%) had recurrent BCC of which 52 (66%) were located on the lower eyelid. Growth patterns were nodular (n=34, 43%), infiltrative (n=25, 32%), micronodular (n=12, 16%), and superficial (n=7, 9%). A third of BCC with a clinically nodular appearance showed additional histological patterns including infiltrative and micronodular growth patterns. Of 30 clinically nodular carcinomas, 29 were excised completely with one level, and one required 2 levels of excision for clearance after evaluation by frozen section. Mean follow-up was 23 months (range 2-60). There was one recurrence (1%). Excision of margins guided by en face frozen section is justified by the low rates of recurrence, and it can easily be taught or imported into hospital practice. Clinically nodular BCC have subclinical extensions that can be missed on bread loaf sectioning, which makes the sampling of margins a standard for periocular BCC.