Clinical factors influencing periocular surgical defects after Mohs micrographic surgery

Purpose: To determine if the surgical defect after excision of periocular s kin cancers can be predicted preoperatively. Methods: Review of medical records of patients who underwent excision of pe riocular skin cancers between 1990 and 1995. Results: Two hundred sixty-four patients (157 men, 107 women) with a total of 281 malignant turners were treated. Basal cell carcinoma accounted for 9 2.2% of the tumors, whereas squamous cell carcinoma constituted 6.4% of les ions. The lower eyelid and medial canthus were the most frequent sites of i nvolvement. Data analysis was conducted on tumor size, cell type, location, and the Mohs stages and sections that were required for cure. Morpheaform basal cell carcinomas required the most Mohs stages and sections and result ed in the largest excisional defects when compared with clinical tumor dime nsions. The lateral canthus had the fewest tumors, but lesions in this area resulted in the largest excisional defects (mean, 9.5 cm(2)) when compared with lesions of the medial eyelid (p = 0.35). The average size of the defe ct after Mohs excision of basal cell carcinoma was 4.2 to 4.6 times the ori ginal clinical tumor size. For morpheaform basal cell carcinoma, however, t he average excisional defect was 6.1 times larger. Conversely, the average defect after excision of squamous cell carcinoma was only 2.6 times as larg e as the original clinical tumor size. Conclusions: These data are useful in predicting the size of a defect after Mohs excision of periocular skin cancer, based on the original clinical tu mor size.